Mohammed Mursi has been formally sworn in as Egypt's president, a day after he pre-empted the formal ceremony by swearing himself in before ecstatic crowds in Tahrir Square and warning off generals trying to curb his powers.
Addressing the "Muslims and Christians of Egypt", Mr Mursi promised a "civil, nationalist, constitutional state", making no mention of the Brotherhood's dream of creating an Islamic order.
He has become Egypt's fifth head of state since the overthrow of the monarchy around 60 years ago.
He took the oath before the Supreme Constitutional Court in their Nile-side courthouse built to resemble an ancient Egyptian temple.
Mr Mursi has vowed to reclaim presidential powers stripped from his office by the military council that took over after Hosni Mubarak's overthrow.
But by agreeing to take the oath before the court, rather than before parliament as is customary, he is bowing to the military's will in an indication that the contest for power will continue.
An army council headed by Field Marshal Mohamed Hussein Tantawi took over from Mubarak last year and has long pledged to make way for an elected president by 1 July.
Egypt remains in political limbo, without a constitution, a lower house of parliament or any clarity about the role of a military establishment anxious to stay in the driving seat.
An assembly that is supposed to write a new constitution has begun work after its predecessor fell apart amid disputes over whether Islamists were over-represented in a country with a 10% Christian minority and many secular-minded liberals.
Mr Mursi narrowly won a run-off vote this month against Ahmed Shafik, a former air force chief and Mubarak's last prime minister, but many voters were dismayed at having to choose between an Islamist and a man seen as a remnant of Mubarak's era.
International Monetary Fund Managing Director Christine Lagarde has called Mr Mursi to discuss the economic challenges facing Egypt and how the international lender can best help, an IMF spokesperson said.
However, no timetable has been set for an IMF staff visit to Egypt to discuss a $3.2 billion IMF loan. That "will depend on the formation of the government," the spokesperson said.
Complicating the process, the generals seized new powers this month, giving themselves veto rights over the drafting of a new constitution, naming a National Defence Council to run defence and foreign policies and decreeing their control of all military affairs.
The military's insistence that Mr Mursi take his oath before the constitutional court and his defiant riposte in Tahrir sets the stage for a protracted struggle for power in Egypt.
The military, the source of every previous president in the Arab republic's 60-year history, also runs business enterprises accounting for an estimated one-third of the economy.
Mr Mursi has said he will respect Egypt's international obligations and does not want to take the country back to war.
