Sultan Ibrahim's son Ahmed Yusuf succeeded him and was one of the most important figures in 19th-century East Africa, receiving tribute from Omani governors and creating alliances with important Muslim families on the East African coast. In Somalland, the Isaaq Sultanate was established in 1750. The Isaaq Sultanate was a Somali kingdom that ruled parts of the Horn of Africa during the 18th and 19th centuries. It spanned the territories of the Isaaq clan, descendants of the Banu Hashim clan, in modern-day Somaliland and Ethiopia. The sultanate was governed by the Rer Guled branch established by the first sultan, Sultan Guled Abdi, of the Eidagale clan. The sultanate is the pre-colonial predecessor to the modern Republic of Somaliland.