Mesih Mehmed Pasha had traveled far before commissioning this mosque. He spent nearly six years in Cairo as governor-general of Egypt — a post of enormous administrative complexity, governing the wealthiest province of the empire. He returned to Istanbul in 1581, climbed steadily through the vizierial ranks, and held the post of grand vizier for exactly four months, from 1 December 1585 until 15 April 1586. He died in 1589, two years after obtaining permission to be buried beside the mosque he had built. That burial location — not in a dedicated tomb but in the open forecourt, at the center of the mosque's rectangular courtyard — was his own choice. Today, visitors cross his grave to enter the building.

The site posed a practical challenge. The land in Fatih slopes, and the eastern side of the plot stands higher than the western. To create a level floor, the mosque's western side was raised on a vaulted substructure that accommodates a row of shops — a characteristic Ottoman solution that used commercial rental income to support religious endowments. The entrance from the street below passes through a domed gatehouse. The forecourt, bounded on three sides by an arcade of small domes, gives the approach a measured, processional quality. Beneath the northern arcade, a series of taps for ritual ablutions lines the wall — the fountain you would expect at a mosque's center replaced here by the tomb of the patron himself.

The main dome covers 12.8 meters in diameter, resting on a drum pierced by 24 windows that flood the interior with light. Eight stabilizing turrets circle the drum, anchored to internal piers. Five half-domes complete the exedra system: one behind the mihrab niche that orients prayer toward Mecca, and one in each corner, giving the interior its characteristic late-Sinan sense of expanding space rather than enclosure. The outer aisles, running along each side, are roofed by three small domes each. Windows at the lower levels are grouped into large framing arches, and the quality of Iznik tiles — documented in surviving photographs — shows the high standards of the Murad III era. The north facade presents a double portico of five arches, the inner row of columns supporting five more small domes above.

What exactly Sinan's hand contributed here will likely never be known with certainty. He was prolific across a career spanning six decades, responsible for hundreds of structures across the empire — from the Süleymaniye to the Selimiye, mosques that define the Ottoman skyline. At the end of that career, attribution becomes complicated. Deputies worked from his templates; he may have reviewed and revised; the foundation inscription records only a completion date, not the full story of the design. That uncertainty is itself a kind of legacy — evidence of an architectural office functioning at imperial scale, where the master's influence pervades work he may never have personally touched.