Nelson Mandela says he tied the knot with Graca Machel under "unbearable" pressure from friends.

The South African president's relationship with Machel was out in the open for two years before their surprise wedding July 18. Members of the clergy complained the couple set a bad example by not getting married."Even in Parliament, deputies told me I should get married," Mandela said Monday. "The pressure became unbearable."

Machel delayed marriage because she didn't want to give up her work and her status in her native Mozambique as the widow of another president.