While Sinan kept the form which had by then already matured and become traditional, his pioneering spirit led him however to make some innovations to this kind of building. Besides some open roofed or baldachin experiments, he produced some original rectangular or square planned tombs, such as that of Yahya Efendi (1571), with its square plan, of Pertev Pasha (1572), with its dilapidated wooden roof, or of Semsi Ahmet Pasha (1580), which differs from the others by being adjacent to the mosque and covered with a cloister vault. As for the Kara Ahmet Pasha Mosque (1558), it is an experiment he was never to repeat. It has two superimposed domes, and a hexagonal shape on the exterior while its interior has twelve sides.
The type of tomb plan Sinan most worked on however was octagon-based. Among tombs which are both externally and internally octagonal shaped and decked with an eaved entrance, we can cite: The Barbaros Hayreddin Pasha Tomb (1541); the Sehzade Mehmet Tomb (1543) remarkable for its fluted dome and drum, the polychrome stonework of its facade, its tiles and the trowel decoration work of its interior; the Husrev Pasha Tomb (1546); and the Rustem Pasha Tomb (1561), with its internally fluted dome.
Sometimes, as in the Haseki Hurrem Sultan (1558) and Sokollu Mehmet Pasha (1574) tombs, the base is octagonal on the exterior while it has sixteen sides on the inside. This base structure was inversed for the tomb Siyavus Pasha, commissioned for himself before his death (between 1582 and 1584), which has sixteen sides on the outside and eight on the inside.
At other times, as in the sehzadeler (1570), Zal Mahmud Pasha (1580) and Kilic Ali Pasha (1580) tombs, the interior may take the shape of four cross-shaped eyvans, with the exterior not corresponding. As for the portico surrounding the octagonal based Piyale Pasha Tomb (1573), it resembles the tomb of Kanuni Sultan Suleyman.
The two important cases in which Sinan departs from the traditional Ottoman form to adopt an almost antique design are those of the tombs of “Kanuni Sultan Suleyman and Selim”. The Kanuni Sultan Suleyman Tomb (1567) is situated in the graveyard adjacent to the mosque of the same name. It has an octagonal base and the lower section is surrounded by a portico. Inside, columns situated slightly in front of the corners are linked to the external walls by paunched arches. A 10.5 m. wide interior dome is supported by eight columns while the exterior dome lies on the outer walls. The dome is decorated with malakc1ri trowel work. Tiles cover the gaps between the windows of the lower row, and the dome pendentives, the band of writings over the windows is also made of tiles. The part remaining over the writings is decorated in marble imitation.
The Tomb of Selim II (1577) holds a special place among the tombs designed by Sinan. Its outward appearance consists of a square prism with bevelled; corners and a superimposed octagonal prism buttressed with four trompes. The entrance porch is both domed and eaved. There is a recess on each side of the; entrance. The wide eave overhangs are supported by iron stanchions. windows\ pierce the dome, opening onto the octagonal prism and its trompes. Behind the porch, the entrance wall rises like a portal up to the dome. Inside, eight columns! are bound together and to the wall by arches. The columns and the octagonall prism are covered by two separate domes. Only the inner dome can be seen from the inside. With its niche like mihrab, its modillioned balcony which advances towards the interior from above the entrance door and its general ;design, the tomb resembles a mosque. The dome is decorated with coloured ornaments in the malakclri trowel work technique. The interval between the lower windows is covered with decorative tiles while the part of the wall situated over the windows is covered all around with writings set on tiles. The outer walls are covered with marble. (For a deeper analysis of the space, see the chapter entitled “Evolution of Space in Sinan’s Works”)
Tombs designed by Sinan exhibit the following characteristics: windows are numerous and form two superimposed rows, which allow increased incoming light to enhance the tiling, ornamental paintings, malakari and other decoration work. Facades have profiled corners, windows and sometimes coloured stones encrusted or set in alternate fashion, with inscription friezes on all sides. Some corners may have embedded columns while the eaves may be crowned with palm leaf motifs made of stone. Entrance porches are frequent. In imperial tombs, tile panels are set beside the entrance door, while the interior is decorated with malakari and tile work. Even if the general structure of the tombs appears to be similar, their interior decoration seems to attempt to reflect the personality of the buried person, with less emphasis on mystical atmosphere.