Updated: Jan. 29, 2011

Hosni Mubarak has been president of Egypt since the assassination of Anwar el-Sadat on Oct. 16, 1981. His tenure is the longest of any Egyptian president since the ouster of the king in the 1950s -- longer than that of Gamal Abdel Nasser, a pioneer of Arab nationalism, and longer than that of Mr. Sadat, who was slain after making peace with Israel.

In the wake of Mr. Sadat's death, Mr. Mubarak continued a policy of maintaining ties with Israel, and cracked down on Islamic militants. His support for Israel won him the support of the West and a continuation of hefty annual aid from the United States. The crackdown on the Islamic Brotherhood forced the militants underground, but as Mr. Mubarak steadily reduced the room for legitimate political dissent, a once-largely secular society has become increasingly Islamicized.

Mr. Mubarak is routinely referred to as Egypt's modern pharaoh, though usually in a cautious whisper. Government critics are routinely jailed and freedom of expression and assembly are restricted.

In January 2011, large protests broke out across the country as thousands called for the end of Mr. Mubarak's rule in the most serious civil unrest in recent memory.

The protesters were mobilized largely on the Internet and energized by recent events in Tunisia, where a popular uprising earlier that month had ended the 23-year-reign of Zine El-Abidine Ben Ali, who, like Mr. Mubarak was a former military man turned autocratic ruler. The protesters in Egypt spoke of the same deep-seated frustrations of an enduring, repressive government that drove Tunisians to revolt: rampant corruption, injustice, high unemployment and the simple lack of dignity accorded them by the state.

Mr. Mubarak appeared on television late on the night of January 28th and ordered his government to resign, but did not offer to step down himself. He backed his security forces’ attempts to contain the surging unrest, saying that while he was “on the side of freedom,” his job was to protect the nation from chaos.

The next day he named Omar Suleiman, Egypt’s military intelligence chief, as the country’s new vice president. It is a post once occupied by Mr. Mubarak and not filled since he took power. State media also said that the country’s new prime minister would be the air force chief, Ahmed Shafik.

But the decision to call out the military appeared to have backfired, as troops and demonstrators fraternized and called for Mr. Mubarak to resign.