Tau cross

Form

A T shape, with no part of the upright above the crossbar, named after the Greek letter tau.

When it is documented

Francis of Assisi (d. 1226) used it as his personal sign.

Context

Francis signed himself with the Tau and used it to autograph his blessing for Brother Leo, the parchment known as the Chartula. Franciscans still use it as a sign of the order.

Links in the Atlas

• Used personally by Saint Francis of Assisi (Saint)

  His own signature sign, attested by Bonaventure and by the Chartula for Brother Leo.

• Traditionally named after Saint Anthony the Great (Saint)

  Also called Saint Anthony’s cross; the origin of that name is not recorded here.

Sources and how they were checked

• Francis signed himself with the Tau (Bonaventure) and used it to autograph the blessing for Brother Leo.

  Secular Franciscan Order of Great Britain, “The Tau Cross” · checked 2026-10-21 (secondary; the Chartula itself, kept at Assisi, was not inspected)

• Names crux commissa, Saint Anthony’s cross, Saint Francis’ cross.

  Wikipedia, “Christian cross variants” — Tau cross · checked 2026-10-21 (tertiary reference)

Not yet known or sourced

• The Franciscan orders are not a collection in the Atlas, so the order link goes through Francis.