Former Egyptian president Hosni Mubarak, whose 30-year rule ended when he was ousted from office during the conflict that came to be known as the Arab Spring in 2011, died Tuesday in Cairo at the age of 91.

Mubarak served as the fourth president of Egypt from 1981 following the assassination of Anwar Sadat, to 2011. His presidency was the longest consistent period of power held by an Egyptian ruler since the founder of the modern Egyptian state, Muhammad Ali Pasha.

A US ally during his rule, Mubarak was overthrown in the uprising of 2011 known as the Arab Spring. His time in office was marked by an uptick in corruption in his Ministry of the Interior and protests against expanded regulations and a police state.

Two months after being ousted from office, in April 2011, Mubarak was arrested and sentenced to life in prison but acquitted on charges he ordered the killing of protesters six years later in 2017. The majority of those years before his acquittal were spent at the Maadi Military Hospital in a guarded room overlooking the Nile.

Mubarak’s death was reported by Egyptian state TV, who offered no other details than information that his death occurred at a Cairo hospital following a surgery he had undergone there.

Last week, two of Mubarak’s sons were acquitted of stock exchange manipulation in an ongoing investigation that began in 2012.