Mandela released from hospital

Nelson Mandela reads an advanced copy of his new book

(CNN) — Former South African President Nelson Mandela was released from a Pretoria hospital after a successful medical examination and an overnight stay, according to a statement from the presidential office Sunday.

Doctors said scheduled tests showed Mandela, 94, is well, the news release said.

Mandela, who has not appeared in public since 2010, has been recovering from a lung infection and gallstone surgery while at his home in Houghton, a suburb of Johannesburg. He was hospitalized in early December and a week later underwent gallstone surgery. He was discharged from the hospital after a two-week stay.

Despite his rare public appearances in recent years, Mandela retains his popularity and is considered a hero of democracy in the nation.

During the time of apartheid in South Africa, Mandela was convicted of sabotage and was imprisoned for 27 years until 1990.

He and former President F.W. de Klerk, who dismantled apartheid, shared the Nobel Peace Prize in 1993. A year later, Mandela became the nation’s first black president.

In November, South Africa issued banknotes bearing Mandela’s picture.

Mandela’s impact has extended far beyond the borders of his own country. After he left office in 1999, he was involved in mediating conflicts from Africa to the Mideast.

Mandela also was treated for an acute respiratory infection in January 2011. The next month he had surgery for an abdominal hernia.