Thomas S. Monson, the 16th president of the Mormon church, has died at the age of 90 in Salt Lake City. Monson, who was named president of the Church of Jesus Christ of Latter-day Saints nine years ago, spent more than five decades on top leadership councils, but largely stayed out of the limelight. However, he was central to the church’s opposition to gay marriage, including during California's controversial 2008 ban, and held the church’s highest position when Mitt Romney became the first Mormon candidate on a presidential ticket in 2012. Per church protocol, the next longest-tenured member of the church’s governing Quorum of the Twelve Apostles, Russell M. Nelson, is expected to take Monson’s place. He is 93.