In ancient times, Yemen was the home of the Sabaeans, a trading state that included parts of modern-day Ethiopia and Eritrea. Later in 275 CE, the Himyarite Kingdom was influenced by Judaism. Christianity arrived in the fourth century. Islam spread quickly in the seventh century and Yemenite troops were crucial in the early Islamic conquests. Several dynasties emerged in the 9th to 16th centuries, such as the Rasulid dynasty. The country was divided between the Ottoman and British empires in the 1800s. The Zaydi Mutawakkilite Kingdom of Yemen was established after World War I before the creation of the Yemen Arab Republic in 1962. South Yemen remained a British protectorate as the Aden Protectorate until 1967 when it became an independent state and later, a Marxist-Leninist state. The two Yemeni states united to form the modern Republic of Yemen (''al-Jumhūrīyah al-Yamanīyah'') in 1990. President Ali Abdullah Saleh was the first president of the new republic until his resignation in 2012 in the wake of the Arab Spring.