Catherine, born in 1347, was the 23rd child (a twin) of Jacopo and Lapa Benincasa in Siena. When she came of age, her parents wanted her to marry, but she insisted that she was betrothed to Christ. In anger, her parents insisted that she act as a servant to the rest of the family. Finally, her father relented and she was allowed to follow her mystic calling. She did not become a nun but joined the third Order of St. Dominic.
Catherine is famous for her Dialogs (written account of her revelations from God) and her Letters wich initially gave spiritual instruction and encouragement, but gradually began to deal with public matters. Many of her letters were directed to popes, kings and other public leaders.
These were the days of the Avignon Papacy, when the pope and his staff have moved from Rome to southern of France. Catherine not only wrote to Pope Gregory XI, respectfully chiding him for leaving Rome, but in 1376 (she was 29 years old) visited him in Avignon and did the same.
Catherine died on this date in 1380, at the age of 33.
In 1970, Pope Paul VI declared her a doctor of the Church.