Ancient Timeline

Pre-Human 13.7 billion- 2.6 million BP (Before Present)	13.7 billion BP (Before Present) Universe born in Big Bang; first atoms along with cosmic microwave background radiation appear 379,000 years later as matter and radiation decouple; almost all hydrogen and most helium existing today created then; first stars appear 100 million years later as gravity concentrates hydrogen atoms, which ignite through nuclear fusion
	13.7-4.6 billion BP Carbon, oxygen, nitrogen, and other elements of life created within stars before birth of Solar System through nuclear fusion near end of stars' lives; elements heavier than iron created primarily through neutron capture in two ways: r-process involving rapid collapse and explosion of massive stars at end of their life into supernovas, and s-process involving slow expansion of second- or third-generation mid-size stars at end of their life into red giants
	4.6 billion BP Sun and planets form from gravitational collapse of gas and dust remaining from previous stars, perhaps brought together initially by shock wave from a supernova; Earth forms 20 million years after Sun in the habitable zone to eventually allow for formation of liquid water, with enough mass to sustain an atmosphere, and with iron in its core to create a magnetic shield, all of which will be necessary for creation of life as we know it
	4.5 billion BP Mars-size planet, named Theia, collides with Earth, creating debris that eventually coalesces into Moon, which stabilizes Earth's rotation and creates stable environment that will eventually be suitable for life
	4.1 billion BP Earth cools enough for oceans, land, and atmosphere to form
	4.0 billion BP Life emerges on Earth as a grouping of carbon-based (organic) molecules by chance makes a copy of itself in primordial ocean or perhaps in volcanic ash; self-replicating groupings of molecules are more successful than groupings that don't replicate and thus become more numerous; competing for limited resources, life begins to evolve into greater competence and complexity to maintain and replicate itself, eventually using simple nucleic acids to replicate, then RNA, then DNA; all life on Earth can likely be traced back to one surviving line of these early organisms, a universal common ancestor
	3.8 billion BP Single-cell organisms emerge, cells being oily bubbles that allow for concentration of favorable molecules and obstruction of unfavorable molecules
	3.6 billion BP Bacteria and bacteria-like archaea, both single-cell organisms that use DNA to self-replicate, evolve from simpler single-cell organisms
	3.5 billion BP Bacteria emerge that use photosynthesis, employing energy from sunlight to convert carbon dioxide into food
	3.0 billion BP Cyanobacteria, also known as blue-green algae (or blue-green bacteria), emerge that produce oxygen as waste product of photosynthesis, beginning oxygenation of atmosphere, which will eventually lead to higher life forms
	2.4 billion BP "Oxygen Catastrophe" results when rising levels of oxygen, which is toxic to most life at the time, kills off most such anaerobic organisms; oxygen beneficial to newer aerobic organisms, enabling cells to process nutrients more efficiently
	2.0 billion BP Complex single-cell organisms, with cell nuclei, emerge when an archaeon captures a bacterium, or a bacterium invades an archaeon, and the pairing by chance leads to the more efficient processing of nutrients for both; such symbiotic bacteria evolve to become energy-producing mitochondria in cells of higher organisms, including humans
	1.2 billion BP Sexual reproduction emerges, with two organisms contributing genetic material to offspring, improving ability of life to adjust to changes in environment, increasing rate of evolution, and allowing for emergence of multicellular organisms
	1.0 billion BP First animal emerges, likely tiny worm-like creature that evolved from a single-cell organism with a whip-like structure at the end, similar to sperm
	850-630 million BP "Snowball Earth" results when Earth freezes over in global glaciation, with entire planet covered by ice; possibly caused by variations in solar output, cyclical changes in Earth's orbit around Sun, or motion of tectonic plates; leads to mass extinction, but life survives under ice; ends as result of reversal of causes and possibly as well by volcanic activity releasing enough greenhouse gases into atmosphere to warm Earth's surface
	540 million BP Cambrian Explosion results when many complex life forms quickly appear, likely resulting from global warming and from oxygen, byproduct of previous ocean bacteria and algae life, reaching high enough threshold to support larger organisms
	510 million BP First fish emerge, without jaws, probably evolving from sea worms
	475 million BP First land plants emerge, evolving from freshwater algae
	425 million BP First animals, arthropods that were ancestors of today's crabs and spiders, crawl out of oceans onto land; not direct ancestors of humans
	400 million BP Amphibians evolve from fish; both direct ancestors of humans
	320 million BP Reptiles evolve from amphibians
	250 million BP Permian Extinction, caused by a surge in vulcanism, a meteor or comet strike, or both; about 95 percent of species on Earth go extinct
	230 million BP Dinosaurs evolve from reptiles surviving Permian Extinction
	200 million BP Mammals evolve from reptiles
	180 million BP Pangaea, last supercontinent, begins breaking up into current continents
	150 million BP Birds evolve from dinosaurs
	65 million BP Dinosaurs and half of all animal species go extinct after a period of increased vulcanism, which gradually warmed climate, followed by an asteroid hitting the Earth near Mexico's Yucatán Peninsula, which quickly cooled climate
	60 million BP Primates emerge, separating from other mammals
	5 million BP Hominids emerge in Africa, separating from other primates
Stone Age 2.6 million BP- 3500 BC	2.6 million BP Homo Habilis, or Handy Man, emerges in Africa, first hominid to make stone tools, first hominid clearly recognizable as us
	1.75 million BP Homo Erectus, or Upright Man, evolves from Homo Habilis in Africa, first to walk truly upright, domesticate fire, and migrate out of Africa; possibility exists that Homo Habilis and Homo Erectus were both descended from a common, and yet unknown, ancestor as they existed together for long time
	250,000 BP Homo Neanderthalensis, or Neanderthal Man, evolves from Homo Erectus in Europe and Asia, or possibly from Homo Heidelbergensis or a similar intermediate species; Neanderthal technology advances little
	200,000 BP Homo Sapiens, or Intelligent Man (modern man), evolves from Homo Erectus in Africa, or possibly from Homo Heidelbergensis or a similar intermediate species; Homo Sapiens only hominid to engage in abstract thinking and symbolic behavior (mythology, art, writing, science, coinage, etc.)
	110,000 BP Homo Sapiens begins migrating out of Africa, crossing Red Sea into Yemen; lines don't survive, according to DNA evidence
	80,000 BP Homo Sapiens, crossing Red Sea into Yemen from East Africa, begins to populate world and eliminate other hominids; it takes about 20,000 years for any group's skin color to change from dark to light as a result of reduced exposure to ultraviolet radiation, according to geneticists; East Africa was possibly Garden of Eden, romanticized and mythologized
	74,000 BP Super volcano erupts in Sumatra, Indonesia, leading to six years of volcanic winter, reducing Homo Sapiens population to 10,000 or less, leaving only fittest surviving
	50,000 BP Homo Sapiens begins arriving in Europe from Persian Gulf region after changing climate eliminates desert barriers in Mesopotamia
	28,000 BP Neanderthal Man goes extinct, likely as a result of being both killed and outcompeted by modern man; DNA evidence suggests little or no interbreeding
	25,000-12,000 BP Homo Sapiens arrives in New World at this time or earlier from Siberia, primarily Mongoloid peoples from East Asia but also Caucasoid peoples from northern Japan; archeological evidence indicates that in this general time frame Americans in small numbers may have arrived by boat from the South Pacific as well as from Europe, who then for the most part must have been eliminated or absorbed by the Siberian immigrants
	10,000 BP/8000 BC Agriculture emerges in Fertile Crescent, region of Middle East incorporating Mesopotamia, Levant, and Egypt (Neolithic Revolution), leading to formation of permanent settlements; 10,000 BP dividing line between Paleolithic (Old Stone Age) and Neolithic (New Stone Age)
	8000 BP/6000 BC Discovery of gold
	5600 BP/3600 BC Continuing melting ice from retreating glaciers of last ice age, which officially ended 10,000 BP, causes huge amount of water from Mediterranean Sea to spill over Bosporos into Black Sea, flooding Black Sea coastal areas; this is what likely led to Great Flood story in Assyro-Babylonian and later Judeo-Christian tradition
Bronze Age 3500-1200 BC	3500 BC Bronze, strong man-made alloy of copper and tin, invented independently in Middle East and Far East
	3300 BC Sumerians, a non-Semitic people in southern Mesopotamia, invent writing, using clay tablets, to keep records of commodities; Sumerians considered by many to be world's first civilization
	3200 BC Sumerians invent wheel and nails; Uruk, in Sumer, is world's first city
	3100 BC Stonehendge, likely a religious center, built in southern Britain
	3000 BC Egyptians, a Semitic people, invent papyrus, with Semitic peoples thought to have originated in Yemen area of Arabian Peninsula
	2800-1450 BC Minoan civilization in Crete, Minoans being a non-Indo-European, pre-Hellenic people; Minoan civilization was likely mythological Atlantis, which ended after a massive volcanic eruption on Santorini (also known as Thera), near Crete
	2700-2200 BC Egyptian Old Kingdom, period of pyramid building
	2500 BC Indo-European speaking peoples begin arriving in Europe from Pontic-Caspian steppe (region northeast of Black Sea and northwest of Caspian Sea corresponding to ancient Scythia and Sarmatia and present-day eastern Ukraine, Russian Volga and Southern districts, and western Kazakhstan)
	2200 BC Mycenaean Greeks, an Indo-European speaking people, begin entering mainland Greece from north, founding cities such as Mycenae, Thebes, and Athens
	2000 BC Italic tribes begin arriving in Italy
	1900 BC Epic of Gilgamesh, best-known of world's first literary works, written in Babylon, Babylonians being a Semitic people
	1800 BC Hittites, an Indo-European speaking people in Asia Minor, invent iron, use for weaponry; iron may have been invented independently in India at about same time
	1755 BC Hammurabi, first king of Babylonian Empire, creates world's first surviving code of laws
	1500 BC Abraham of Ur in southern Mesopotamia leads Hebrews, a Semitic people, from Sumer to Canaan and then, as result of famine, to Egypt
	1500 BC Celts begin arriving in Britain from Gaul (France)
	1500 BC Work begins on Vedas, oldest scriptural texts of Hinduism, emphasizing ethical actions and spiritual practices to liberate individuals from egoism and cycle of birth and rebirth
	1250 BC Trojan War, possibly a semilegendary fusion of several wars, pitting Mycenaean Greeks against Greeks from Troad region of Asia Minor
	1200 BC Moses leads Israelites (Hebrews) from Egypt into Canaan
Iron Age 1200-800 BC	1200 Widespread use of iron begins in Mediterranean region; Iron Age doesn't begin in Central Europe until 800 BC and Northern Europe until 600 BC
	1200-1100 BC Dorians (Spartans) immigrate from north into Greek mainland, ending Mycenaean civilization, Sea Peoples, who may have been Philistines (from Canaan) or Greeks or both, invade Mediterranean coasts, destroying Hittite Empire; Dorians and Sea Peoples succeed with use of iron weaponry
	1100-1000 BC Ionians (Athenians), displaced by Dorians, immigrate into Asia Minor
	1100 BC Writing ceases in Greece and Asia Minor, ushering in Dark Age, as a result of Dorians and Sea Peoples crushing earlier civilizations; Greek city states ruled by kings
	1050 BC Phoenicians, a Semitic people living in present-day Lebanon and skilled in ancient times as seafaring traders, invent phonetic alphabet, with about two dozen abstract symbols (letters) representing sounds, in contrast to non-alphabetic writing systems such as Sumerian cuneiform, Egyptian hieroglyphs, and Chinese characters in which thousands of originally representational pictures depict things or actions; Arabic, Hebrew, Indic, Greek, and Latin alphabets derived from Phoenician alphabet; Phoenician alphabet represents only consonants, not vowels
	930 BC Israel and Judah separate into two kingdoms; some time afterward priests in each kingdom begin writing down oral traditions that eventually coalesce into Bible
	900 BC Dorians (Spartans) immigrate into Peloponnesos, Aegean islands, and Lycia, Asia Minor
Archaic Age 800-500 BC	800 BC Writing reappears in Greece; Greeks invent first alphabet with vowels
	800-700 BC Monarchies in Greece begin to be replaced by aristocratic republics
	776 BC First Olympic games
	750 BC Greek colonization intensifies
	621 BC Draco institutes code of law in Athens, its first written constitution
	610 BC Lydians of Asia Minor invent coinage; shortly afterward it spreads to Greek cities in Asia Minor, then Greek islands, then Greek mainland, then rest of world
	600 BC Thales of Miletos, Ionia, Asia Minor, first philosopher in Greek tradition and "father of science"; offers naturalistic explanations of world in contrast to magical, miraculous, and mythological stories that have remained central to most religions up to and including the present
	600 BC China issues its first coins, cast bronze pieces in shape of farm tools
	560 BC Lydians invent bimetallic coinage, issuing coins of pure gold and pure silver
	546 BC Cyrus the Great, founder of Persian Empire, conquers Lydia as well as Greek territories in Asia Minor
	509 BC Monarchy in Rome is replaced by aristocratic republic
	507 BC Kleisthenes ushers in world's first democracy in Athens, with power shared by male citizens (excluded women, slaves, freedmen, and non-Athenians)
	500 BC Buddha teaching in India, emphasizing non-craving to bring relief from suffering; Confucius and Lao-tzu teaching in China, former emphasizing morality, latter harmonious action
Classical Age 500-330 BC	499-495 BC Unsuccessful Ionian revolt against Persian domination of Greek Asia Minor
	490 BC First Persian invasion of Greece; Battle of Marathon
	480-479 BC Second Persian invasion of Greece; Persians defeat Spartans at Thermopylae; Persians occupy Athens; Greeks defeat Persians at Salamis
	477 BC Athens-dominated Delian League formed to unite Greece against Persians
	449 BC Greeks and Persians make peace, the Peace of Callias
	443-429 BC Pericles is leader of Athens during its Golden Age
	431-404 BC Athens fights and loses Peloponnesian War to Sparta, ending its military domination of Greece
	399 BC Socrates dies in Athens; laid foundation of Western philosophy, emphasizing questioning of assumptions, reason, and self-knowledge
	395-340 BC Warfare among rival Greek leagues
	392 BC Rome begins conquest of Italy, sacking Etruscan city of Veii
	386 BC Plato founds Academy in Athens, first institute of higher learning in Western world; Plato's thinking about dualism of world into ideal and sensual, that people who regard natural world knowable by senses as real and good are ignorant and should be scorned, would informed later Christianity and influence what modern world became; Platonism, however, was based on reason, Christianity on faith
	382 BC Celts of Gaul sack Rome
	338 BC Philip of Macedonia founds League of Corinth, ends autonomy of Greek city states
	336-323 BC Alexander the Great's reign; conquers Persian Empire and most of known world east of Greece, spreading Greek culture
	335 BC Aristotle founds Lyceon in Athens, institute of higher learning; as opposed to Plato, emphasizes study of natural world
Hellenistic Age 330-30 BC	323-148 BC Greek city states remain relatively independent; frequent warfare continues among rival leagues
	300 BC Ptolemy I, Macedonian king of Egypt, begins building Library of Alexandria, world's first public library designed to be repository of world's knowledge; likely destroyed by Christians in late 4th or early 5th century AD
	300 BC Euclid in Alexandria writes Elements of Geometry, compendium of his work and others; becomes one of most commonly used text books of all time
	280 BC Celts arrive in the Balkans and Asia Minor
	264-146 BC Rome defeats Carthage in three Punic Wars, establishing dominance in western Mediterranean
	221 BC China unites for first time, under Qin (Ch'in) dynasty
	215 BC Rome introduces denarius, silver coin replacing slightly larger drachm; serves as main Roman coin denomination for 500 years; evolves into French denier and English silver penny and later both English copper penny and U.S. cent
	200-196 BC First Roman victories over Greece
	168 BC Rome wins Third Macedonian War
	148 BC Rome annexes Macedonia, making it Roman province, and begins stripping it of material wealth
	146 BC Rome conquers Greece, sacking Corinth and ending Greek independence
	88-86 BC Athens joins revolt against Roman rule led by Mithradates the Great of Pontos, Asia Minor, which ends in sack of Athens by Roman general Sulla
	73-71 BC Spartacus leads unsuccessful revolt of Roman slaves
	64 BC Rome annexes Syria
	57 BC Caesar conquers Gaul
	55 BC Caesar invades Britain
	50 BC Rome introduces the gold coin aureus
	36 BC Mayans in Central America first to use symbol for zero
	31 BC Octavian defeats Antony and Cleopatra and annexes Egypt, ending Hellenistic Age
Roman Empire 27 BC-476 AD	27 BC Octavian becomes Augustus, first Roman emperor
	27 BC-180 AD Pax Romana, 200-year period of relative peace within Roman Empire, corresponding to pinnacle of Roman influence, ending with death of emperor Marcus Aurelius
	9 AD Rome loses the Battle of Teutoburg Forest to the Germanic Cherusci tribe, ending its northern expansion
	30 AD Crucifixion of Jesus
	43 AD London founded as Roman settlement
	70 AD Roman emperor Titus destroys Temple of Jerusalem and sacks the city, leading to the diaspora of the Jews to Armenia, Iraq, Iran, Arabia, Egypt, Italy, Spain, and Greece
	105 AD China invents paper
	267 AD Gothic tribes (East Germanic tribes that probably originated in southern Sweden) sack Byzantium, Athens, and Corinth
	306-337 AD Rule of Constantine the Great, first emperor to fully embrace Christianity; moves Roman capital to Byzantium, renaming it Constantinople
	360 AD Beginning of the intensification of Germanic incursions into Roman territory, with Visigoths, Ostrogoths, Vandals, Burgundians, and Franks increasingly threatening Roman hegemony in the West
	360-363 AD Reign of Julian the Philosopher, last Roman emperor who tried to restore classical paganism; this failure more than anything else led to a dark age, a thousand years of dogmatism, darkness, and decline in which observation, experimentation, and original thinking were suppressed, a period longer than the traditional Dark Ages of 476 to 1000 AD, a period that began reversing itself during the Renaissance in the 14th century with the rediscovery of classical learning
	379-395 AD Reign of Roman Emperor Theodosius, who makes Christianity Rome's state religion and begins persecuting non-Christians, banning the Olympics
	410 AD Rome withdraws from Britain
	449 AD Germanic tribes of Anglo-Saxons begin invading Britain, displacing Celts
	452 AD Attila the Hun invades Italy
	476 AD Romulus Augustulus, last Western Roman emperor, exiled and replaced by Germanic king Odoacer; traditionally considered end of the Roman Empire, though the Eastern Roman Empire of the Byzantines, with Constantinople as its capital, would last until 1453
Note: Many of the above dates are approximate and debatable; some early events are commonly accepted theories; division of time into particular ages is partly from a Western perspective. See Traveling back in time: Nature's Objects for photos and descriptions of several natural objects that span the eons.