The idea of Pangaea, the supercontinent that existed millions of years ago, was first proposed by Alfred Wegener, a German meteorologist and geophysicist, in 1912. Wegener's theory of continental drift, which suggested that the continents had moved over time and were once part of a single landmass, was initially met with skepticism from many scientists. However, over time, as evidence accumulated, Wegener's theory gained acceptance and eventually became a fundamental concept in geology.