19th Century archaeologist Christian Thomsen devoloped the idea of progressive human development and proposed a "Three Age System" to describe the assumption. The three ages, Stone, Bronze and Iron are still used to describe time periods in non-technical terms, but Thomsen's names for the ages are now considered outdated. His underlying theory, however, is the basis of much of modern archeology.

In North America fluted stone arrowheads dated to 10,000-11,000 years before present at Blackweel Draw, a prehistoric site near Clovis, New Mexico, where discovered by local residents in 1929. The discovery resounded across the archeological world, pushing the date of inhabitation of the North American continent back further then previously thought.

Discoveries were made that indicated even earlier dates of inhabitation in North America. From Pennsylvania, Virginia, and Wisconsin came astonishing discoveries that challenged the Clovis claim of oldest. Each time valid questions were raised, but the body of pre-Clovis evidence was growing. Then came word of the work at Monte Verde in Chile, where Tom Dillehay of the University of Kentucky had dated artifacts back to 12,000 BC, significantly older than Clovis. Yet the so-called "Clovis-first" advocates found issues with the dig and refused to recognize an earlier date.

That is until University of South Carolina Professor Albert Goodyear, himself a "Clovis-first" advocate, discovered small flaked stone tools more than a meter beneath the suspected Clovis layer at the "Topper Site" along the South Carolina and Georgia border in 1998. According to Archeology Magazine, Goodyear returned to the site because of the Monte Verde discoveries and the lesser finds in North America. Topper (named for a local man who led Goodyear to the site) shook the archeological community, possibly pushing the date of earliest inhabitation on the North American continent to well before 20,000 BC and revolutionizing the direction of inhabitation -- some of the artifacts exhibit similarities to Old World Upper Palaeolithic bone and wood working implements known as burins.