In 1748, four years after Tello’s precipitous departure, maestro de albañil (master brick mason) Geronimo Ybarra and the maestro cantero (master stone-cutter) Felipe de Santiago were hired to complete San Fernando parish church, probably begun by Tello. During this work, Ybarra and Santiago were each paid two pesos and a meal per day. In 1750 the Franciscans paid for transportation costs of Ybarra’s wife to San Fernando. Four years later, in 1754, Mission Concepción paid for the transportation of Felipe de Santiago’s wife to San Antonio.
According to his testimony in a lawsuit in 1756, Ybarra began working on San Fernando church on the 28th of October, 1748, and completed the building sometime in 1755. Ybarra tore down the old parish church which was 71.2 feet long and 17.8 feet wide, and had a tower. The new church was of stone, had transepts and a tower (presumably with a spiral staircase inside it), and was 31 .5 feet high to the parapets of the nave, 20.6 feet wide and 90.4 feet long. The roof was a vault of wood set on the ribs. Santiago finished the fine carving for the parish church in l754, and moved to Concepción full time in that year.
While he worked on the parish church, Ybarra began working part-time for the missionaries about 1750. Although he lived at San Antonio de Valero, his first task was supervising church construction at Concepción. The Franciscans probably decided to have Ybarra begin work at Concepción because its church was in better condition and closer to completion than the poorly constructed and partially collapsed building at Valero. Ybarra and Santiago clearly began with some part of Tello’s facade already standing at Concepción, and probably at Valero. Some additional carved stone may have been finished and awaiting assembly; but at some point, on both facades, the stone carving changed from that of Tello to those of Ybarra and Santiago.
After the completion of Concepción in 1755, Ybarra began working on projects at the other missions. Between 1755 and 1756, Ybarra carried out major construction at Valero, Espada, and San Juan, and continued work on the Concepción convento; but there is no suggestion that he did any work after the l759 visita report. We are left to assume that Hieronymo Ybarra was fired or quit, or died in 1760.