South African President Nelson Mandela's honorary law degree from Harvard puts him in heady company.

Mandela, 80, is one of only three people to receive an honorary degree from Harvard at a time other than the university's commencement exercises. The others were George Washington in 1776 and Winston Churchill in 1943.

The honor "holds great symbolic significance to the mind and to the future memory of this great American institution -- the name of an African is now added to those two illustrious leaders," Mandela said to a standing ovation of more than 8,000 Friday in Harvard Yard.

Mandela, who spent 27 years in prison in a fight against apartheid and won the Nobel Peace Prize in 1993, accepted the degree and then called for an end to economic disparities worldwide.