Adal's headquarters were again relocated the following century, this time southward to Harar. From this new capital, Adal organised an effective army led by Imam Ahmad ibn Ibrahim al-Ghazi (Ahmad "Gurey" or "Gran"; both meaning "the left-handed") that invaded the Abyssinian empire. This 16th-century campaign is historically known as the Conquest of Abyssinia (''Futuh al-Habash''). During the war, Imam Ahmad pioneered the use of cannons supplied by the Ottoman Empire, which he imported through Zeila and deployed against Abyssinian forces and their Portuguese allies led by Cristóvão da Gama. Some scholars argue that this conflict proved, through their use on both sides, the value of firearms such as the matchlock musket, cannon, and the arquebus over traditional weapons.