During this time the Egyptians remained in the region to solidify control, only leaving in 1840 as the Ottomans again took direct control over the region of Mecca and Medina, with nominal control over nearly the entire peninsula other than the far south.
In 1916 the British and French, fighting the Ottomans at the time in World War I, encouraged the Arabs to begin a revolt and take their lands. This was led by the Sharif of Mecca and he gained great support throughout the peninsula and further north. With Ottoman defeat in WWI, the British granted the Arabs a state in the Arabian Peninsula, but not to the extent promised. Additionally, British support soon shifted from the Sharif of Mecca to the Al Saud family.
By this time, about 1920, the Al Saud family, led by Abdul Aziz, had returned from exile, had re-taken Riyadh, and had begun taking various lands in the surrounding areas, all but defeating the Al Rashid in 1920. The Al Saud takeover truly climaxed in 1925 when they took the Hejaz region in the country's southwest, declaring himself king in 1927, which the United Kingdom recognized. In 1932 the regions of Hejaz and Nejd were united to form the Kingdom of Saudi Arabia.
In the 1930s power was solidified with the discovery of oil as by the late 1940s this export supported the entire economy. The government also established great relations with Western Europe and the United States when they supplied these countries with oil during World War II.
As the oil industry blossomed the country was faced with vast cultural changes as foreigner began making their way to the region. This led to ethnic tensions, overspending, and increased technology, but with backlashes to maintain conservatism. This led to a change in leadership, brought about by the royal family.
During the years, in the 1950s and 1960s the government oddly turned to the United States to help develop infrastructure. The U.S. had created their oil industry with success so was sought again to help create improved roads, airlines, automobiles, communication, and technology. This has created a long and positive relationship between the two countries.
In 1967 civil war in Yemen led to tensions with Egypt as Saudi Arabia supported the current government and the Egyptians supported the protesters. Due to this, Saudi Arabia refused to participate in the Arab-Israeli war in the same year to show their dissatisfaction with Egypt. Also in the 1960s Saudi Arabia got more involved with their neighbors as they exchanged land with Jordan and supported, financially their neighbors who were at war with Israel.
The relations with the United States took a dip in 1973, during another Arab-Israeli war when Saudi Arabia boycotted exporting oil to the United States in fear that they would send their oil to Israel. It was also during this time that the Organization of Petroleum Exporting Countries (OPEC) was established and as they created limited supplies they saw increasing prices and much larger profits, making Saudi Arabia an extremely wealthy country and that time and into today.
The 1970s were also a challenging time for Saudi Arabia as they faced pressure from their Shi'ite minority in the east and Islamic extremists in the west. The extremists viewed the changes in the country and cooperation with the United States as un-Islamic. This led to stricter religious laws in the country, but the extremists continued their protests.
In the 1980s the economy grew further as the country became the world's largest oil producer. They also used much of this money to improve their military.
The 1990s were headlined by the Iraqi invasion of Kuwait. Saudi Arabia has long had a good relationship with Kuwait and this led to their intervention in the situation, also requesting that the United States defend Kuwait, allowing U.S. soldiers to be station in Saudi Arabia.
In the 2000s Saudi Arabia is again seeking a balance as they spoke out again the United States' invasion of Iraq in 2003, but are also seeing a rise in Islamic extremists. This has led to recent military actions to end these extremists as the country has spoken out again former Saudi national Osama bin Laden who was exiled from his home country before being killed in 2011.