Ottoman architecture evolved over time as the empire's capitals changed location. Bursa, Edirne, and Istanbul each marked a stage in development and allowed influences from Byzantine and other cultures. A key architectural form was the kulliye, a religious complex centered around a mosque that included other buildings like madrasas, hospitals, and baths. Over time, Ottoman architects like Mimar Sinan developed distinctive styles like dominating mosques situated atop hills that gave cities their silhouette. Kulliyes were separated from residential areas and emphasized the vertical rather than public spaces.