The Vatican said Tuesday that Viganò is stepping down because he has reached the age of retirement.
Viganò drew attention in September when he invited controversial Kentucky clerk Kim Davis to meet Francis during the pontiff’s visit to the United States.
The Vatican said at the time that the unexpected visit was planned by Viganò, who had been known to speak against same-sex marriage more forcefully than others in the church.
As a veteran of the Vatican’s outpost in Mexico and several other spots in the world, Pierre may be able to continue Francis’s focus on immigration issues, particularly at the U.S.-Mexico border. When the South American pope visited Mexico in February, he prayed with migrants at the U.S. border.