Though the sultan was the supreme monarch, the sultan's political and executive authority was delegated. The politics of the state had a number of advisors and ministers gathered around a council known as Divan (after the 17th century it was renamed the "Porte"). The Divan, in the years when the Ottoman state was still a Beylik, was composed of the elders of the tribe. Its composition was later modified to include military officers and local elites (such as religious and political advisors). Later still, beginning in 1320, a Grand Vizier was appointed to assume certain of the sultan's responsibilities. The Grand Vizier had considerable independence from the sultan with almost unlimited powers of appointment, dismissal and supervision. Beginning with the late 16th century, sultans withdrew from politics and the Grand Vizier became the de facto head of state.
A Grand Vizar began to be appointed in what year?
1320