The four-color theorem asks whether every map drawn on a plane or sphere can be colored with just four colors so that adjacent regions always have different colors. First posed by Francis Guthrie in 1852 while coloring a map of England, it remained unsolved for over a century until Kenneth Appel and Wolfgang Haken proved it in 1976.

Early attempts to solve the problem involved prominent mathematicians like Augustus De Morgan, who received the question from his student Frederick Guthrie in 1852. De Morgan corresponded with William Rowan Hamilton about the problem but made a crucial error in his reasoning. The earliest known printed mention appeared in 1854 in *The Athenaeum*, and the problem later reached America through Charles Sanders Peirce at Harvard.

The problem gained new momentum in 1878 when Arthur Cayley raised it at a London Mathematical Society meeting. Cayley made significant progress by showing how the general problem could be reduced to cubic maps - those with exactly three regions meeting at each point. This reduction technique, where patches are added to points where more than three regions meet, became an important step toward the eventual proof.

This mathematical puzzle's 124-year journey from a simple observation about map coloring to a computer-assisted proof marked a turning point in mathematics, demonstrating how computational methods could solve problems too complex for traditional pen-and-paper approaches.