The Pre-Republic Era

c. 7,500,000,000 BBY
 The first star in the Cularin system, named Morasil, is formed.
c. 5,000,000,000 BBY
 Korriban is formed.
 The Yavin system is formed.
c. 2,000,000,000 BBY
 The Oseon system is formed. A rogue star is believed to have passed too close to the system, disrupting the planet formation and creating an abnormally large asteroid belt.[1]
c. 10,000,000 BBY
 Volcanic activity on Esseles begins to end.
c. 7,500,000 BBY
 First sentient species in the galaxy begin to evolve.[source?]
c. 4,000,000 BBY
 The Valley of the Giant Oysters on Dac begins to form.
c. 3,000,000 BBY
 An asteroid collides with the planet Vinsoth, killing most life on its surface. The remaining survivors evolve into the Chevin.[2]
c. 2,006,200 BBY
 The Columi first evolve.
c. 2,004,200 BBY
 The Columi take to trees and begin to develop for arboreal life.
c. 2,002,200 BBY
 The Columi learn to use tools.
c. 2,002,000 BBY
 The Columi, with their newly acquired skill of mining for minerals, begin building tree spanning cities.
c. 2,000,000 BBY
 The Columi achieve interstellar travel.[3]
 Wookiees begin to evolve on Kashyyyk.[2]
 Beggar's Canyon is formed on Tatooine.
 Sullustans evolve underground on Sullust.
 The Pelgrin construct their Oracle.
c. 1,000,000 BBY
 Feeling threatened by the Celestials, the Sharu go underground and hide their cities in order to protect themselves.
 The Corellian system is presumably formed by the Architects.
 The Hutts leave Varl and settle on the planet they dub Nal Hutta.[source?]
 The Bith undergo a terrible war.
c.999,989 BBY
 According to Dr. Corellia Antilles, by this time, most sentient species have begun keeping historical records, though at least some of those records prove indecipherable to modern historians.[4]
c. 999,975 BBY
 Sernpidal takes Dobido as its moon.
c. 750,000 BBY
 Goroth begins to develop intelligent life.
c. 500,000 BBY
 The Devaronians achieve space travel.[3]
 Naboo undergoes an ice age.[source?]
 The Gree evolve.
c. 499,989 BBY
 By this time, according to Dr. Corellia Antilles, most sentient species have records decipherable to modern historians.[4]
c. 300,000 BBY
 The Gree civilization enters its golden age. clarify[5]
c. 200,000 BBY
 The Taungs of Coruscant attempt to conquer the 13 baseline Human nations of the Battalions of Zhell.
 A volcano on Coruscant erupts, decimating the Zhell.
 The Taung flee to the planet Roon.
c. 130,000 BBY
 Sith society begins.
c. 100,000 BBY
 The planet Coruscant is now covered entirely by its principal city, later known as Galactic City.[6]
 The Sith race begins to develop their culture and civilization on the planet Korriban.
 The Columi survey Coruscant and Duro, dismissing them as "primitive" disappointments.[7]
 The Kwa construct the Infinity Gate[7] and the Star Temples on Dathomir.
 Civilization on Goroth begins with an agricultural society.
c. 95,000 BBY
 The last time the lower levels of Coruscant reportedly see sunlight.
c. 57,000 BBY
 Utapau is colonized[2] by humanoid species that would later evolve into the Pau'an and Utai species.
c. 50,000 BBY
 The Gree develop hypergates.
c. 49,000 BBY
 The Rakata develop a special form of hyperdrive.[7]
c. 40,000 BBY
 Felucia is colonized by the Gossam.
 The civilization on Garos IV is wiped out by a groundquake.
c. 36,453 BBY
 Philosophers and scientists from several star systems gather on Tython to share mystical knowledge. The Force is discovered.[8]
c. 35,000 BBY
 The Castle Lands of Oroboro are built by the Killiks on Alderaan.
 The Infinite Empire of the Rakata is officially established.[9]
c. 30,000 BBY
 The Infinite Empire reaches its peak and constructs the Star Forge.[10]
 The Killiks are driven from Alderaan and Alsakan.
 The Sith King Adas unifies the Sith nations on Korriban.
c. 29,000 BBY
 The Kashi Mer Dynasty reaches its height.
c. 27,700 BBY
 The Rakata arrive on Korriban. Adas leads the Sith to victory over the alien invaders but is killed in the process.
c. 27,500 BBY
 The first Human colonists land on Alderaan.[11]
c. 27,000 BBY
 Human colonists first arrive in the Tion Cluster.
c. 26,000 BBY
 The Morodins colonize Varonat.
 The Library of Xer is built on Criton's Point.
 The Cult of M'dweshuu is formed on the Nikto homeworld of Kintan.
 Alsakan is colonized by Humans from Coruscant in the colony ship, Kuat Explorer.
c. 25,793 BBY
 Several Tythonian scholars begin to use their knowledge of the Force to pursue power. A conflict ensues which devastates Tython.[8]
c. 25,783 BBY
 The Jedi Order forms from the ashes of Tython's Force Wars.[8]
c. 25,200 BBY
 A Major plague sweeps through the galaxy that kills only Rakata. As a result of this, twinned with subject species rebellions, the Infinite Empire collapses.[10]
 The Kitel Phard dynasty is founded on Atrisia.
25,180 BBY
 The Verpine colonize the Roche asteroid field.
c. 25,130 BBY
 The reign of Xim the Despot begins.[12]
c. 25,105 BBY
 The Battle of Ko Vari and the First Battle of Vontor are fought between the Hutt Empire and the empire of Xim the Despot.
c. 25,100 BBY
 Both the Second and Third Battles of Vontor are fought between the Hutts and Xim the Despot.
 According to Tionese history, Xim the Despot is killed at Vontor, but he is actually captured and later dies as a slave in the dungeons of Kossak on Evocar.
 The Treaty of Vontor is signed.
 The Hutts gain control of the Si'Klaata Cluster.

Source: starwars.wikia.com