ROME – Pope Francis on Saturday praised the zeal of an 18th-century Franciscan missionary he will make a saint when he visits the United States this fall but whom Native Americans say brutally converted indigenous people to Christianity.

Francis praised Junipero Serra during a homily at a Rome seminary training future priests from North America. The pope will proclaim the Spaniard a saint during a Washington, D.C., ceremony Sept. 23.

Native Americans have protested in California, saying the friar should be criticized for what they contend was his role in wiping out native populations in a campaign to impose Catholicism. They contend he enslaved converts and that missionaries like him helped spread diseases like smallpox which decimated their people.

Francis described Serra as part of a missionary corps who “went out to all the geographical, social and existential peripheries” to spread the Gospel.

“Such zeal excites us,” Francis said.

Serra, who died in 1784, “ushered in a new springtime of evangelization in those immense territories, extending from Florida to California,” Francis said. The Vatican sees Serra as a role model for the growing U.S. Hispanic Catholic population.

The soon-to-be saint also helped defend “indigenous people against abuses by the colonizers,” Francis contended.

Without wading into specific criticisms of Serra, Francis said of these missionaries: “Sometimes we stop and thoughtfully examine their strengths and, above all, their weaknesses and shortcomings.”

Native Americans are outraged that Serra is becoming a saint, blaming him and other missionaries for nearly eradicating their culture.

“No Indians pray to Serra here,” said Ron Andrade, a member of the La Jolla Indian Reservation and director of the Los Angeles City and County Native American Indian Commission.

When Spanish missionaries moved up the coast in their quest for new souls, “we moved inland, we moved away from the churches,” Andrade said in a phone interview about Francis’ honoring Serra. “(Serra knew) by destroying the culture and the lifestyle (of Native Americans), they would die.”

The missionary work was done to “acquire land and souls, whether they were alive or dead,” Andrade said. He also lamented that the pope “didn’t sent out his bishops to ask if there was anything to be ashamed of” about Serra.

In Francis’ homily, the church’s first Latin American pope expressed awe for the likes of Serra, saying “I wonder if today we are able to respond with the same generosity and courage” in leaving comfortable lives to proclaim God to those who haven’t “experienced the embrace of his mercy.”

Before celebrating Mass at the seminary with Francis, Washington Cardinal Donald Wuerl dismissed concerns that canonizing Serra could be a divisive act offending Native Americans.

“The message of the Holy Father is reconciliation,” Wuerl said.

Native Americans, including inter-tribal council members in California, have been lobbying for the removal of a statue of Serra from the U.S. Capitol.