Was he poisoned or did he die of natural causes?

Beyazit was 33 when he became sultan and, unlike his father, was not a military man preferring the peace of Topkapi Palace to the campaign lifestyle.  For the first year of his reign he was engaged in a war of succession with his brother Cem, who declared himself Sultan of Anatolia and rallied an army of supporters at Bursa.  Beyazit eventually won this war and Cem fled to Rhodes.  Beyazit now turned his attention to yet more building in the imperial city starting with a mosque complex, Beyazit Camii, which can still be seen adjacent to the Covered Bazaar – in fact that whole district became known as Beyazit.  During the 1490s Beyazit gave refuge in Constaninople to many Jews who had been expelled from Spain, and this Jewish community was still in existence until the 1980s when political events in Turkey encouraged them to emigrate yet again.

From 1508 onwards Beyazit, now in his sixties, was in failing health and bed-ridden.  He had three remaining sons (five others were already dead) all serving as provincial governors in Anatolia and each with their eye on the imperial throne.  One of them, Selim, knowing that Beyazit wanted to abdicate in favour his oldest son Ahmet, marched his army across to Europe and, in April 1512 entered Istanbul and took control of the city.  He met with his father, whom he hadn’t seen for twenty-six years, forced him to abdicate and on 24 April Selim was girded with the sword of Osman and became Sultan Selim I.

Beyazit left the city some three weeks later officially bound for retirement in Demotika in Thrace.  He died en route, perhaps as a result of poison administered by his doctor on the orders of the new Sultan Selim.  His body was brought back to Istanbul and interred in the Beyazit Mosque.