Catherine was the twenty fourth or twenty fifth child of a Sienese dyer, and her family wanted her married. She cut off her hair, refused, was set to work as a household servant to break her resistance, and outlasted them. She then joined the Mantellate, Dominican tertiaries, mostly widows, who wore the habit and lived at home rather than in a convent, and she spent about three years in near total silence in a room in her father's house.
That period ended with what she describes as an instruction to go out, and everything afterwards is public. She nursed plague victims and lepers in Siena, gathered around her an unlikely following of men and women, priests, poets and politicians, who called her Mamma although she was younger than nearly all of them, and began dictating letters. Nearly four hundred survive, addressed to popes, to the king of France, to a queen of Naples, to mercenary captains, to prisoners under sentence of death.
Their tone is the striking thing. She writes to Gregory XI addressing him as Babbo, daddy, and telling him in the same breath to stop being a coward and to act like the man God appointed. She could not write when she began and dictated to secretaries; she learned later. No woman of her century occupied a comparable public position without either royal birth or a religious office, and she had neither.