Theodosius Florentini (23 May 1808 at Münster, in the Grisons, Switzerland – 15 February 1865 at Heiden, in Appenzell) was a Swiss Capuchin monk, a founder of Catholic religious orders and institutions.
He entered the Capuchin Franciscan Order, 22 October 1825, was ordained priest in 1830, and appointed novice master, and lecturer on philosophy and theology. In 1838 he became guardian at Baden; in 1845 superior and parish priest at Chur; in 1857 definitor, and in 1860 vicar-general of the Diocese of Chur.
After the Sonderbund war, the Radical party opposed Catholic interests. In consequence of his defence of the Church, Father Theodosius fled to Alsace in 1841. In August of the same year he returned. He founded the Institute of the Franciscan Sisters of the Holy Cross. In the Capuchin church at Altorf on 16 October 1844, the first three sisters received the habit of the Third Order of St. Francis. Their constitutions enjoin upon them to make themselves all to all in order to win souls to Christ and to do nothing which might repel any from their mode of life. From this foundation grew the congregation of teaching sisters, with their mother-house at Menzingen.
Later on Father Theodosius founded the congregation of Sisters of Mercy at Ingenbohl. Both were actively engaged in educational works; the Sisters of Mercy set up, besides, homes for the poor and sick, and undertook private nursing.
In the meantime Father Theodosius was himself busy as a schoolmaster. He superintended the people's schools (Volksschulen), which are attended by others besides the poor. He promoted continuation schools and was in favour of technical instruction for apprentices and workmen. He founded anew the suppressed Jesuit College, Maria-Hilf zu Schwyz. To stir up anew Catholic life he engaged in popular missions and retreats for priests.