linguistic:translation
19th century and later

In the early 19th century, Bahrain was invaded by both the Omanis and the Al Sauds. In 1802 it was governed by a 12-year-old child, when the Omani ruler Sayyid Sultan installed his son, Salim, as governor in the Arad Fort. In 1816, the British political resident in the Persian Gulf, William Bruce, received a letter from the Sheikh of Bahrain who was concerned about a rumour that Britain would support an attack on the island by the Imam of Muscat. He sailed to Bahrain to reassure the Sheikh that this was not the case and drew up an informal agreement assuring the Sheikh that Britain would remain a neutral party.

In 1820, the Al Khalifa tribe were recognised by the United Kingdom as the rulers ("Al-Hakim" in Arabic) of Bahrain after signing a treaty relationship. However, ten years later they were forced to pay yearly tributes to Egypt despite seeking Persian and British protection.

In 1860, the Al Khalifas used the same tactic when the British tried to overpower Bahrain. Writing letters to the Persians and Ottomans, Al Khalifas agreed to place Bahrain under the latter's protection in March due to offering better conditions. Eventually, the Government of British India overpowered Bahrain when the Persians refused to protect it. Colonel Pelly signed a new treaty with Al Khalifas placing Bahrain under British rule and protection.

Following the Qatari–Bahraini War in 1868, British representatives signed another agreement with the Al Khalifas. It specified that the ruler could not dispose of any of his territories except to the United Kingdom and could not enter into relationships with any foreign government without British consent. In return the British promised to protect Bahrain from all aggression by sea and to lend support in case of land attack. More importantly the British promised to support the rule of the Al Khalifa in Bahrain, securing its unstable position as rulers of the country. Other agreements in 1880 and 1892 sealed the protectorate status of Bahrain to the British.

Unrest amongst the people of Bahrain began when Britain officially established complete dominance over the territory in 1892. The first revolt and widespread uprising took place in March 1895 against Sheikh Issa bin Ali, then ruler of Bahrain. Sheikh Issa was the first of the Al Khalifa to rule without Persian relations. Sir Arnold Wilson, Britain's representative in the Persian Gulf and author of The Persian Gulf, arrived in Bahrain from Muscat at this time. The uprising developed further with some protesters killed by British forces.

Before the development of the petroleum industry, the island was largely devoted to pearl fisheries and, as late as the 19th century, was considered to be the finest in the world. In 1903, German explorer Hermann Burchardt visited Bahrain and took many photographs of historical sites, including the old Qaṣr es-Sheikh, photos now stored at the Ethnological Museum of Berlin. Before the First World War, there were about 400 vessels hunting pearls and an annual export of more than £30,000.

In 1911, a group of Bahraini merchants demanded restrictions on the British influence in the country. The group's leaders were subsequently arrested and exiled to India. In 1923, the British introduced administrative reforms and replaced Sheikh Issa bin Ali with his son. Some clerical opponents and families, such as Al Dosari, left or were exiled to Saudi Arabia. Three years later the British placed the country under the de facto rule of Charles Belgrave who operated as an adviser to the ruler until 1957. Belgrave brought a number of reforms such as establishment of the country's first modern school in 1919 and the abolition of slavery in 1937. At the same time, the pearl diving industry developed at a rapid pace.

In 1927, Rezā Shāh, then Shah of Iran, demanded sovereignty over Bahrain in a letter to the League of Nations, a move that prompted Belgrave to undertake harsh measures including encouraging conflicts between Shia and Sunni Muslims to bring down the uprisings and limit the Iranian influence. Belgrave even went further by suggesting to rename the Persian Gulf to the "Arabian Gulf"; however, the proposal was refused by the British government. Britain's interest in Bahrain's development was motivated by concerns over Saudi and Iranian ambitions in the region.

The Bahrain Petroleum Company (Bapco), a subsidiary of the Standard Oil Company of California (Socal), discovered oil in 1932.

In the early 1930s, Bahrain Airport was developed. Imperial Airways flew there, including the Handley Page HP42 aircraft. Later in the same decade, the Bahrain Maritime Airport was established, for flying boats and seaplanes.

Bahrain participated in the Second World War on the Allied side, joining on 10 September 1939. On 19 October 1940, four Italian SM.82s bombers bombed Bahrain alongside Dhahran oilfields in Saudi Arabia, targeting Allied-operated oil refineries. Although minimal damage was caused in both locations, the attack forced the Allies to upgrade Bahrain's defences, an action which further stretched Allied military resources.

After World War II, increasing anti-British sentiment spread throughout the Arab World and led to riots in Bahrain. The riots focused on the Jewish community. In 1948, following rising hostilities and looting, most members of Bahrain's Jewish community abandoned their properties and evacuated to Bombay, later settling in Israel (Pardes Hanna-Karkur) and the United Kingdom. As of 2008, 37 Jews remained in the country. In the 1950s, the National Union Committee, formed by reformists following sectarian clashes, demanded an elected popular assembly, removal of Belgrave and carried out a number of protests and general strikes. In 1965 a month-long uprising broke out after hundreds of workers at the Bahrain Petroleum Company were laid off.