Historians of numbers have long noted that 11 makes a team.

For example: the 11-strong team of detectives charged with identifying murderers in ancient Rome; the 11-strong vice squad of women established by the Spartan state to keep a lid on Dionysiac orgies; or the 11-monstrous giant-beasts who assisted Tiamat, lord of chaos in his doomed battle against the pantheon of Babylon led by the king of the gods, Marduk.

Of course, the main 11 in modern life is that of football teams. The 11 traditional positions are: goalkeeper, left back, right back, left half, centre-half and right half, and the five forward positions – left wing, inside left, centre-forward, inside right and right wing.
However, as illustrated by the classic lineup (below) that won England's only World Cup title in 1966, the formations have long had different permutations, most commonly with the outfield players arranged as 4–3–3 or 4–4–2.

You would imagine that the 11 players in a football team must have some significance, for the game is as old as humanity, but in its early centuries football was often played by hundreds of people. The game as we know it today was developed largely in the English public schools of the 19th century and first codified in the "Cambridge Rules" of 1848, thrashed out from the various schools different traditions. Oddly, there was no mention of the number of players in a team then, nor in the earliest surviving set of rules from 1856, though the number had been accepted by the time the FA Cup was established in 1871. It may have followed the example of cricket, with a convenient division of five attackers, five defenders and a goalkeeper.

Rugby, of course, went its own way in the 19th century, allowing not just the handling and carrying of the ball but a player count of 13 or 15.

Tomorrow: 12 signs of the zodiac

• Taken from Rogerson's Book of Numbers by Barnaby Rogerson (Profile).