Haft Gumbad, or "Seven Domes," lies outside the city of Gulbarga to the east and contains the tombs the later Bahmani sultans. The earliest tomb is that of Mujahid (d. 1378/779 AH), but the most important is that of Firuz (d. 1422/825 AH), which shows the fully evolved Bahmani style and is the largest and best decorated of the group. Other tombs in the group include that of Da'ud (d. 1378/779 AH) and Ghiyath al-Din (d. 1397/799 AH).
The tombs of Da'ud and Firuz both consist of two domed chambers linked by a narrow interior corridor, forming a double mausoleum, while the tombs of Mujahid and Ghiyath al-Din are typical square plan single domed monuments.
Sources:
Merklinger, Elizabeth Schotten. Indian Islamic architecture: the Deccan 1347-1686, 109-111. Warminster, England: Aris & Phillips, 1981.
Merklinger, Elizabeth Schotten. Sultanate architecture of pre-Mughal India, 127-128. New Delhi: Munshiram Manoharlal Publishers, 2005.