Nine Men's Morris belongs to the family of mill games, where players try to make rows of three pieces. The game is old enough that its exact beginning is hard to pin down, and some early board markings are debated rather than settled.

What is clear is that the game travelled well. It needed only a drawn board and two sets of counters, so it could be played with stones, seeds, coins, or carved pieces.

Writers often connect Nine Men's Morris with Roman-era play, and related board patterns have been found or claimed in older archaeological settings. Some famous early claims, including boards associated with Egypt, are disputed because carved patterns can be difficult to date.

By the Middle Ages the game was common in Europe. Boards were carved into benches, stone seats, and other shared surfaces, which says a lot about how informal the equipment could be. People did not need a manufactured set to play.

The game also shows up in English cultural history. Shakespeare refers to Nine Men's Morris in A Midsummer Night's Dream, which suggests the board was familiar enough for an audience to recognize it.

The game has been known by several names, including mills, merels, merrills, and morris. Smaller and larger relatives exist too, such as Three Men's Morris, Six Men's Morris, Twelve Men's Morris, and Morabaraba.

The flying rule is one of the rules that varies by source. Some versions allow a player with three pieces left to jump to any empty point; other versions keep movement limited to connected points. This site uses the flying rule because it keeps the endgame playable for the side that is close to losing.

Nine Men's Morris has been studied by computer-game researchers. With perfect play, the standard game is generally treated as a draw, but real games still have plenty of room for mistakes, traps, and practical wins.