9th century (801–900 CE / 184–288 AH) 801: Death of Rābiʿa al-ʿAdawiyya al-Qaysiyya famous Arab Muslim saint and Sufi mystic. 802: The Mecca Protocol: Caliph Harun al-Rashid and the leading officials of the Abbasid Caliphate perform the hajj to Mecca, where the line of succession is finalized. Harun's eldest son al-Amin is named heir, but his second son Abdallah al-Ma'mun is named as al-Amin's heir, and governor of Khurasan. A third son, al-Qasim, is added as third heir, and receives responsibility over the frontier areas with the Byzantine empire. 803: Downfall of the Barmakids. Execution of Ja'far ibn Yahya. Marriage of caliph Harun al-Rashid and Umm Muhammad bint Salih. 805: Outbreak of revolt of Rafi ibn al-Layth in Khurasan. 806: Harun al-Rashid leads a huge campaign against the Byzantines. 809: Death of Harun al-Rashid. Accession of al-Amin. 810: Muhammad al-Taqi, the 9th Shia Imam was born. 811: Abbasid Civil War: Battle of Rayy in Persia. 812, August: Abbasid Civil War: the Siege of Baghdad begins 813, September: Abbasid Civil War: the Siege of Baghdad ends with the capture of the city by the forces of al-Ma'mun and the death of al-Amin 813: Tahir ibn Husayn appointed as Governor of Mosul by Al-Ma'mun 815: Zaydi revolt under Abu'l-Saraya in Iraq. Harthama ibn A'yan quells the revolt. 816: Shi'a revolt in Mecca; In al-Andalus the Umayyads capture the island of Corsica. Harthama ibn A'yan is executed. 818: Ali al-Rida dies in Mashhad. Muhammad al-Taqi becomes Imam. The Umayyads of Spain capture the islands of Ibiza, Majorca, and Sardinia. 820: Tahir ibn Husayn, Caliph al-Ma'mun appointed Tahir as Governor of Khorasan. In 820 Abdallah ibn Tahir was appointed governor of Syria. 822: Death of al-Hakam I in Spain; accession of Abd ar-Rahman II. 822: Death of Tahir in Khurasan. Talha was appointed Governor by Al-Ma'mun in 822. Jafar ibn al-Mu'tasim (future Al-Mutawakkil) born in Baghdad. ca. 825: Establishment of the Emirate of Crete. 826: Abdallah ibn Tahir, appointed as Governor of Egypt. 827: Ali al-Hadi, the 10th Shia Imam is born. Ma'mun declares the Mu'tazili creed as the state religion. Beginning of the Muslim conquest of Sicily. 828: Abdallah ibn Tahir appointed as Governor of Khorasan by Al-Ma'mun in 828. 833: 9 August— Death of Ma'mun. Accession of al-Mu'tasim. 835: Muhammad al-Taqi is poisoned. Ali al-Hadi becomes Imam. 836: al-Mu'tasim moves the capital to Samarra. 837: Revolt of the Jats. 838: Revolt of