The Almohads were a Berber Muslim dynasty that emerged in the 12th century in North Africa. They originated from the Atlas Mountains and sought to reform Islam by emphasizing strict monotheism and rejecting the practices of the Almoravids, their predecessors. The Almohads expanded their territory, controlling parts of modern-day Morocco, Algeria, and Spain. Under leaders like Abu Yaqub Yusuf, the Almohads established a vast empire and promoted cultural and intellectual advancements. They are known for their architectural achievements, including the Koutoubia Mosque in Marrakech and the Giralda in Seville. Their rule lasted until the late 13th century, when they began to decline.