Sheikh Dhiyab bin Isa (ruled 1761-1793) Built Qasr Al Hosn as a watchtower to guard over the only freshwater well on Abu Dhabi island.
Sheikh Shakhbut bin Dhiyab (ruled 1793-1816) Expanded the tower into a small fort and transferred his ruling place of residence from Liwa Oasis to the fort on the island.
Sheikh Tahnoon bin Shakhbut (ruled 1818-1833) Expanded Qasr Al Hosn further as Abu Dhabi grew from a small village of palm huts to a town of more than 5,000 inhabitants.
Sheikh Khalifa bin Shakhbut (ruled 1833-1845) Repaired and fortified the fort.
Sheikh Saeed bin Tahnoon (ruled 1845-1855) Turned Qasr Al Hosn into a strong two-storied structure.
Sheikh Zayed bin Khalifa (ruled 1855-1909) Expanded Qasr Al Hosn further to reflect the emirate's increasing prominence.
Sheikh Shakhbut bin Sultan (ruled 1928-1966) Renovated and enlarged Qasr Al Hosn, adding a decorative arch and two new villas.
Sheikh Zayed bin Sultan (ruled 1966-2004) Moved the royal residence to Al Manhal palace and kept his diwan at Qasr Al Hosn.
Sources: Jayanti Maitra, www.adach.ae