WILLIAMSBURG, Va. — The president of the College of William & Mary, who drew heavy criticism for removing a cross from the nation’s oldest college chapel, resigned Tuesday after the public school’s board told him his contract would not be renewed.

Gene Nichol’s decision, effective immediately, was outlined in an e-mail to the university community. The Board of Visitors, which advised Nichol on Sunday that his contract would not be renewed in July, confirmed his departure.

“Mine, to be sure, has not been a perfect presidency,” Nichol wrote in the e-mail. “I have sometimes moved too swiftly, and perhaps paid insufficient attention to the processes and practices of a strong and complex university. A wiser leader would likely have done otherwise.”

In his e-mail, he also charged that, in addition to the cross flap, his efforts to improve diversity at the college have proved controversial.

In October 2006, Nichol sparked loud protests when he removed the cross from permanent display in Wren Chapel to make students and visitors of non-Christian faiths feel more welcome at the nation’s second-oldest college.

Some outraged alumni and students sought to remove Nichol from office. One donor rescinded pledges to give $12 million to the school, and angry state lawmakers weighed in on the matter.

The cross was returned to the chapel in August in a locked, Plexiglas-like case near the altar. It can be removed from the case and placed on the altar by request.

Nichol defended his decision in his e-mail Tuesday. “We are charged, as state actors, to respect and accommodate all religions, and to endorse none. The decision did no more,” he said.

The departing president also received criticism for allowing a show on campus last week that featured monologues and performances by porn actors, strippers and other sex workers. Nichol said Tuesday that he would have violated the First Amendment had he banned the show from the student-governed speaker series.