John Timon, first American provincial of the Vincentian Fathers, prefect apostolic of Texas, and first Bishop of Buffalo, New York, son of James and Eleanor Leddy Timon, was born at Conswego Settlement near York, Pennsylvania, on February 12, 1797. In early 1800 his family moved from Pennsylvania to Baltimore, where James prospered as a merchant for a few years. In the meantime John, in September 1811, entered St. Mary's College. The following year he attended Mount St. Mary's College in Emmitsburg, Maryland. During the course of the next few years he became increasingly attracted to the clerical state of life. After an unsuccessful venture in business with his father, he entered the Vincentian order in Perryville, Missouri, on September 23, 1826. After ordination Father Timon entered missionary work in the lead-mining region of Missouri, the area from where Moses Austin and his family had made their excursion into Texas a few years earlier. In 1835, after having served the Catholic Church in the Missouri area for several years, Timon was named provincial of the American Vincentians. In that capacity he became involved with the missionary efforts being planned for Texas by the Holy See. During the Texas Revolution and the period of the republic the Catholic faith remained firmly fixed among the Mexican people of Texas, but among immigrants from the United States the authority of the bishop of Monterrey, Nuevo León, had weakened. In 1837 prominent Texas Catholics made an appeal to the American hierarchy for clergy.
In 1838 Pope Gregory XVI took steps to relieve the church's distressed condition in the Lone Star republic. He gave ecclesiastical jurisdiction over Texas to Bishop Anthony Blanc of New Orleans and authorized him to send priests to the region. Blanc, in turn, selected Father Timon to head the mission. The Vincentians thus assumed responsibility for Catholicism in Texas, with Father Timon named prefect apostolic in the fall of 1839. Timon's greatest contribution to the Catholic history of Texas is that as prefect he sent Father Jean Marie Odin to the republic. Timon himself, accompanied by Father John Francis Llebaria, made an initial survey of the condition of Catholicism in Texas between December 26, 1838, and January 12, 1839, thus laying the groundwork for the Vincentians under Bishop Odin. During this trip Timon celebrated the first Mass in both Galveston (December 28, 1838) and Houston (January 3, 1839). In 1841 the Vatican elevated the republic to the status of a vicariate apostolic with Bishop Odin as vicar apostolic, and Timon ceased to function as prefect apostolic. Nevertheless, this devoted Vincentian and good friend of Odin actively supported the cause of the church in Texas until his own appointment as bishop of Buffalo, New York, in 1847. Timon died in 1867.