From the museum website.
On the eastern slope of Rózsadomb the Tomb of Gül Baba reminds us of the time when the majority of Hungary was under Turkish reign. Suleiman I decided to invade the Castle of Buda on the spring of 1541 so it would not be seized by the Hungarian king.
The sultan entrusted the members of the Bektash order to build an Islam religious center close to the town before the arriving of the army. The members of the order were usually priests, dervishes, but occasionally they performed the tasks of soldiers too. Their leader was Gül Baba, who was well known of his piety, poems, and his love of nature. According to the legend his name came from the rose he wore on his turban, but others believe that his name came from the piece of textile he wore on his dervish hat which symbolizes mystic knowledge.
After Suleiman reached Buda in August he asked the Queen to surrender peacefully, in exchange he offered the eastern half of the country. So the Turkish army occupied the capital on 29th August, 1541. On 2nd September while giving a sermon, Gül Baba died.
There were several ideas of his death; some said that he was very old, according to others he got wounded at the fights and he received his death from Allah as the nicest present. His body was laid to rest in the garden of the tomb.
The chapel was built in 1543-1548. Since the desecration of the tomb it has been a place of pilgrimage whish was visited by pilgrims coming from long distances and in great numbers. The tomb is a very old sacred place of the Islam, it was built at the period of the 5th or 6th Empire, and it is also the northernmost Islam sacred place.
Buda was recaptured in 1686. After the Turkish left, the Jesuits received the area including the tomb, which was consecrated to St. Joseph and turned to a Christian chapel. The lead dome was taken off and a shingle roof was put up. On the wall two oval shaped windows were opened. After the disintegration of the Jesuit order in 1773, the hillside was placed under the authority of the town.
In 1914 the chapel was declared a monument and its renovations began. The researchers found a body which was identified as Gül Baba. On 1st July, 1915 the remains of Gül Baba were ceremonially replaced in the ground and the grave was sealed.
The restorations were completed in 1918 and the monument opened for the Muslim pilgrims.
In WWII the mansion that surrounded the tomb was bombed down, but it saved the tomb from serious damages. Restoration works were performed at the beginning of 1960s: the dome was replaced and the two window openings were walled in. At the beginning of 1970s a terrace was built around the tomb.
By the beginning of the 1990s the condition of the tomb became critical. Tamás Pintér was entrusted with making the plans of restorations which were financed by the Turkish authorities. Throughout the restoration a portico was built, two fountains covered with marble, and a real Turkish café and an exhibition ward was organized for the visiting Muslim tourists and pilgrims. The opening ceremony was held on 21st August, 2000, since then this distinctive place with its unique atmosphere can be visited.