Muhammad I began construction of the Alhambra Palace in Granada in 1238. He was the founder of the Nasrid dynasty and the first emir of the Emirate of Granada.
After establishing Granada as his capital, Muhammad I moved from the older Zirid citadel on the Albaicín hill to the Sabika hill. There, he developed an existing fortress into a new royal residence and military citadel. Early work included defensive walls, towers, an irrigation system, and the Alcazaba.
The Alhambra was not completed by one ruler. Muhammad I laid its foundations, while later Nasrid sultans expanded the complex into a palatine city. Muhammad II and Muhammad III continued the work, and Ismail I, Yusuf I, and Muhammad V added or transformed many of the palaces and courtyards visitors recognize today.
A common mix-up is to credit Yusuf I or Muhammad V because much of the surviving decorative palace architecture dates from their reigns. Muhammad V, for example, built the celebrated Palace of the Lions. However, the original construction of the Alhambra as a Nasrid royal fortress began under Muhammad I.