The term third order signifies, in general, lay members of Christian religious orders, who do not normally live in a religious community such as a monastery and yet can claim the right to wear the rel
Catherine of Siena (1347–1380), as a Dominican tertiary, lived outside religious institutions, and had a diplomatic career
The Mystic Marriage of Saint Catherine of Siena by Giovanni di Paolo, c. 1460 (Metropolitan Museum of Art, New York).