The Omani Invasion of Bahrain and the "Century of Madness"

The Omani Invasion:

During the beginning of the 18th Century, an Afghan uprising (in Afghanistan) and subsequent invasion of Persia by the Afghans caused regional instability which resulted in the Persians pulling out their garrisons from Bahrain. Taking advantage of the confusion, the Sultanate of Oman (in 1717), then a regional power in the Gulf, invaded the island thus lifting 115 years of Safavid control of the island.

The Bahraini cleric, Shaikh Yousif al Bahrani (the cleric I previously mentioned) provided a detailed account of this invasion in his autobiography and book:

The earth shook and everything came to a standstill while preparations were made to do battle with these vile men [the Khārijite Omani invasion force]. The first year they came to seize it they returned disappointed, for they were unable to do so. Nor were they able to succeed the second time a year later, despite the help they received from all of the Bedouin and outlaws. The third time, however, they were able to surround Bahrain by controlling the sea, for Bahrain is an island. In this way they eventually weakened its inhabitants and then took it by force. It was a horrific battle and a terrible catastrophe, for all the killing, plunder, pillage, and bloodshed that took place.

After the Khārijites had conquered it and granted the inhabitants safe passage, the people—especially the notables—fled to al-Qaṭīf and other regions. Among them was my father—God have mercy upon him—accompanied by his dependents [i.e., wives] and children, who traveled with them to al-Qaṭīf. But he left me in Bahrain in the house we owned in al-Shākhūra because some chests filled with bundles of our possessions, including books, gold coins, and clothes, were hidden there. He had taken a large portion of our possessions up to the fortress in which everyone had planned to [take refuge] when we were besieged, but he had left some behind in the house, stored in hiding places. Everything in the fortress was lost after the Khārijites took it by force, and we all left the fortress with nothing but the clothes on our backs. So when my father left for al-Qaṭīf, I remained in Bahrain; he had ordered me to gather whatever books remained in the fortress and save them from the hands of the Khārijites. I did manage to save a number of books that I found there along with some that were left in the house, which I sent to him a few at a time. These years passed in an utter lack of prosperity.I then traveled to al-Qaṭīf to visit my father and stayed there two or three months, but my father grew fed up with sitting in al-Qaṭīf because of the large number of dependents he had with him, the miserable conditions, and his lack of money, so he grew determined to return to Bahrain even though it was in the hands of the Khārijites. Fate, however, intervened between him and his plans, for the Persian army, along with a large number of Bedouins, arrived at that time to liberate Bahrain from the hands of the Khārijites. We followed the events closely and waited to see the outcome of these disasters; eventually the wheel of fortune turned against the Persians, they were all killed, and Bahrain was burned. Our house in the village [of al-Shākhūra] was among those burned.During this time, I was traveling back and forth to Bahrain in order to take care of the date palms we owned there and gather the harvest, then returning to al-Qaṭīf to study. [This continued] until Bahrain was taken from the hands of the Khārijites by treaty, after a great sum had been paid to their commander, because of the Persian king's weakness and impotence, and his empire's decline through bad administration. 

Political Limbo in Bahrain:

No clear historical evidence suggests that the Omanis had stayed for a significant period of time aside from the data above. It is widely believed that Bahrain had been pillaged by the Omanis simply for wealth. However, when the Omanis had left, political instability in the island had led to many invasions by Huwala Bedouins. These were Sunni Arabs who had migrated to Persia in the early centuries, it also applies vice versa( Sunni Persians settling in Arabia). Al Bahrani says that these tribes had 'ruined' Bahrain.

A map (in Arabic) showing the extent of the Omani Empire

Almost constant warfare between various Sunni bedouin tribes, the Kharajite Omanis and then the Persians under Nadir Shah (who had sought to re-establish Persian dominance in the island) and Karim Khan Zand laid waste to much of Bahrain, while the high taxes imposed by the Omanis drove out both the ulema,pearl merchants and the pearl divers .

In 1736, Bahrain had been recaptured by Persia , along with the aid of the British and the Dutch. But afterwards, it was ruled by the Arabs of Abu Shahr of the Bushire-based Al Madhkur family but it was indirectly a vassal state to (then De Facto Shah) Karim Khan of the Safavids.

The years of almost constant warfare and instability in the period led to a demographic collapse - German geographer and Arabist 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 Akhbaris in Bahrain (Bet you thought they all died out :P )