Refers to the style and period that coincided with the reign of Orhan, 1324 to 1362. The earliest royal mosques built during this period were of two types. The first was the single-domed chamber with or without a portico. The second type consisted of a five-part portico leading to a domed central chamber, which on axis opened through an arch to the mosque proper. Two flanking chambers, probably barrel-vaulted, opened into both the porch and the domed chamber. In 1339, Ohran began a similar mosque at Bursa, with a domed chamber preceding the central space, and double flanking rooms opening into the central chamber. Also of this period, is the "Silver Tomb" of Osman, so named for its gleaming lead dome.