Before 19th Century

: The oldest form of starlight is this old. In the year 2001, and would often discuss the fact that they would look up at billion year old starlight. 
:
4,500,000,000 BC
A rock blasts off the face of Mars by a meteor impact. It ends in Earth's atmosphere and lands in what will be Siberia. It contains dormant biological organisms capable of entering living bodies. 
; Over 350 million years ago
: In Earth's Surilian period, cockroaches are believed to have originated. 
; 100 million years ago
: The remains of various dinosaurs begin the process of transforming into crude oil. :: A meteor crashes into north Alaska. This meteor contained an worm that thrived on ammonia, that would survive for 250,000 years ::: In 2000, Shelly Mizer jokingly claimed to have played music with Jason Guthrie during this time :: "A quarter of a million years ago."
: While following strange tracks through the snow of North Texas, two cavemen are attacked by an . One of the primitives is killed by the creature, while the other dies of exposure to the alien's . The bones of the primitive men will later be discovered in 1998. ()::: Ancient Egyptian history begins around 3000 BC, with the earliest evidence of agriculture around 10,000 BC. This would still be during the Pleistocene epoch, and is the time when the Hall of Bulls cave art was painted in France. Amen-Re was first worshipped in 2400 BC. The actual Great Seal was (believed to be) invented in 1776.
:: The earliest image of the Great Seal is known to exist, representing the god Amen-Re. 
; 6th century BC: Pythagoras discovers the power of numbers and comes up with the field of numerology. 
; 4 BC: Jesus Christ is born in Bethlehem. 
; 10th century: A ceremonial axe is created to cleave open skulls of those who do not follow Christianity. 
: "Over a thousand years" before 2000.
Circa 1300
The Anasazi culture disappears in the Southwest. Some of their elders hide in one particular pueblo that contains magnetite, protecting them from the aliens. The thinks of these elders as "the first shadow government." 
1513
Mulder speculates that if anyone actually found the Fountain of Youth and remained living in the forest, they might have adapted to their environment and become significantly changed. 
1776
13 colonies of British North America declare their independence from Great Britain, forming the United States. 
 Distant past