Daunting challenge for Egypt's new president
It is a victory that just two short years ago would have been inconceivable. Now the Muslim Brotherhood have control of the presidency in the largest country in the Arab world.
Mohammed Mursi went into this final round of the election a divisive figure. Even before his victory, he tried to counter this, by stressing his message of unity, something he quickly repeated in his first televised address.
His first advantage: it will be difficult for anyone to challenge the legitimacy of his victory. It would be very hard to claim that the electoral machinery was biased in favour of the Muslim Brotherhood.
Next, he will have a hard, cold look at how much real power that he can wield.
In its edicts and actions over the last 10 days, the ruling military council has reasserted control over a wide swathe of policy. It will have power over foreign and defence policy. With parliament dissolved, it can propose legislation. The military will also have an effective veto over the writing of the constitution.
Egyptians are longing for the return of normality, and the chance to rebuild the country's prosperity - that's the biggest thing going for Mohammed Mursi”
That still leaves the new president with power to appoint a prime minister and a government, and with wide power over domestic policy. It was notable that one of the first messages of reassurance from Mohammed Mursi was directed at the police and the security services, who must be extremely nervous about their position.
Whatever his theoretical power, with the office of president Mohammed Mursi automatically takes on enormous authority. This country has been used to rule by one strong figure since the time of the pharaohs.
But many Egyptians will be innately suspicious. They have been warned for decades that the Muslim Brotherhood want to take over Egypt and turn it into an Islamic republic.
Even since the revolution, the Brotherhood promised not run a presidential candidate, and not to contest a majority of seats in parliament. Both promises were broken. There will be plenty of Egyptians who fear their agenda is to "islamise" Egypt.
Mohammed Morsi can quickly provide real reassurance. His choice of prime minister will be watched closely. He has already pledged to appoint someone from outside the Brotherhood. He can send a similar message of reassurance with his appointments of vice presidents and cabinet ministers.
Egypt is deeply polarised, but at the same time Egyptians are longing for the return of normality, and the chance to rebuild the country's prosperity. That's the biggest thing going for Mohammed Mursi, as he moves to tackle Egypt's daunting list of problems after more than a year of political gridlock.