Isidro Félix de Espinosa (1679–1755) was a Franciscan missionary from New Spain who participated in several expeditionary missions throughout the province of Tejas (modern Texas).
[2] On April 5, 1709, an expeditionary group made up of Father Espinosa and Father Antonio de Olivares, along with Captain Pedro de Aguirre and fourteen soldiers, traveled to the area which today is San Antonio, Texas, to establish a Spanish colony, attracted by the presence of water resources in that region.
[4] In late April 1716, another Espinosa and Ramón expedition traveled to east Texas to establish a Spanish colony in the area.
He earned the nickname of El Julio Cesar de la Fé en Nueva España (The Julius Caesar of Faith in New Spain).
[4] A letter written by Espinosa in February 1718 is now the second or third oldest document known to have used New Philippines, the official name of New Spain's most northeastern province during the 18th century.
[7] In late 1721, Espinosa was appointed guardian of the missions established by the Queretaro college in Tejas, but he left the region at that time and never returned.