Both Uses

Francis of Assisi
in
Romeo and Juliet
(Edited)

Holy Saint Francis! What a change is here!
p. 89.1

Saint Francis = an Italian and the Roman Catholic monk who founded the Franciscan order
Saint Francis be my speed!
p. 229.1 *

Definitions:

(1) (Francis of Assisi)
Italian, Roman Catholic monk who founded the Franciscan order (1181-1226)

St. Francis of Assisi was known for his love of animals. Statues of him with animals are often seen in gardens. He is the patron saint of animals and the environment.

St. Francis of Assisi is the best known of numerous Roman Catholic Saints who may be referred to as St. Francis.
(2) (meaning too rare to warrant focus)
Less commonly, Saint Francis can refer to another Catholic saint, or to places and institutions named after them.