Franciscus is a Latin masculine given name, originally an epithet meaning "the Franks". It is also used as a surname. There are many related names. Etymology and meanings. The Medieval Latin word Francus or Franciscus, meant "belonging to the people of the Franks", a Germanic people of central Europe. The Franks derived their tribal name from a type of throwing axe that they used as a weapon during the early Middle Ages. The Franks were the only tribe who had rights of free citizens in the Middle Ages, so the term frank came to mean a free, sincere, or true.
https://en.wikipedia.org/wiki/Franciscus