VENTURA, Calif. — On his way to Mass every morning at Mission San Buenaventura, Miguel Olivas drives past the bronze statue of the Catholic mission’s founder, Junípero Serra, a Spanish Franciscan friar, and murmurs a plea: “Pray for me, Father Serra. Watch over me.”

But to Jorge Escamilla, Father Serra — who will be canonized by Pope Francis on Wednesday in Washington — is much more than a source of spiritual solace. He is also a vital touchstone, signaling the importance of Latinos in the multicultural history of the Catholic Church and the United States.

“He spoke Spanish. I speak Spanish. The pope speaks Spanish,” Mr. Escamilla said gleefully after a packed Spanish Mass last Sunday at San Buenaventura, explaining why he will be one of thousands traveling to Washington for the canonization. “I belong.”