the ruler of Bahrain, Shaikh Jubayr, was away on hajj. The invasion brought the island back under central rule and to challenge Oman in the Persian Gulf. He sought help from the British and Dutch, and he eventually recaptured Bahrain in 1736. In 1753, Bahrain was occupied by the Arabs of Abu Shahr of the Bushire-based Al Madhkur family, who ruled Bahrain in the name of Persia and paid allegiance to Karim Khan Zand. During the Qajar era, Persian control over Bahrain waned The years of almost constant warfare and instability in the period led to a demographic collapse – German geographer Carsten Niebuhr found in 1763 that Bahrain's 360 towns and villages had, through warfare and economic distress, been reduced to only 60. The influence of Iran was further undermined at the end of the 18th century when the ideological power struggle between the Akhbari-Usuli strands culminated in victory for the Usulis in Bahrain. Invasion and British Protectorate The Bahrain invasions In 1782, war broke out between the army of Sheikh Nasr Al-Madhkur, the ruler of Bahrain and Bushehr and the Zubarah-based Bani Utbah clan, though hostilities arose since 1777 after the Persians saw the Zubarah base as a threat. The prosperity of Zubarah, which is in modern Qatar, had brought it to the attention of the two main powers at the time, Persia and Oman, which were presumably sympathetic to Sheikh Nasr's ambitions. At the same time, Bahrain offered great potential wealth because of the extensive pearls found in its waters. Nasr enlisted the aid of the rulers of Bandar Rig, Bandar Ganaveh and Dashtestan and amassed an army of 2,000 soldiers to be commanded by his nephew, Mohammed. The Persians launched an assault of Zubarah's fort but were forced to break the siege after suffering stiff resistance from the Al Khalifa defenders and facing imminent naval reinforcements from Bani Utbah men in Kuwait. In retaliation to the assault, the Bani Utbah clan launched an invasion of Bahrain Island in 1783. Historians disagree on who attacked first; some historians believe that the incoming naval reinforcements from Kuwait intercepted a message from Nasr Al-Madhkur to his representative in Bahrain stating that the Persians had lost the battle. Upon learning this, the fleet switched course and invaded Bahrain, capturing the Bahrain fort and surrounding the Persian garrison. With a large coalition of tribesmen from the Bani Utbah and interior Arabia,