Short answers, pulled from the story.
Baghdad was founded by the Abbasid Caliph Al-Mansur on the 30th of July 762. Construction was guided by two designers: Naubakht, a Zoroastrian astrologer, and Mashallah, a Jew from Khorasan, Iran, who calculated an auspicious founding date under the sign of Leo.
The House of Wisdom, known in Arabic as Bayt al-Hikmah, was a major academy in Baghdad that by the middle of the 9th century held the largest collection of books in the world. It was the center of the Abbasid translation movement and hosted scholars including mathematician al-Khwarizmi and philosopher Al-Kindi.
Baghdad was captured by the Mongols on the 10th of February 1258, led by Hulegu, a grandson of Genghis Khan. The caliph Al-Musta'sim was killed, large sections of the city were destroyed by fire and looting, and the canals and dykes of the city's irrigation system were demolished. The sack ended the Abbasid Caliphate.
By 1900, Baghdad's Jewish population was approximately 50,000, comprising over a quarter of the city's total population at that time. In 1948, Jews numbered roughly 150,000, constituting 33% of the city's population. After successive waves of violence and emigration, an estimated 160 Jews remain in Baghdad today.
The Farhud was a pogrom against Baghdad's Jewish community that took place on the 1st and the 2nd of June 1941, during a power vacuum following a failed pro-German coup. Over 180 Jews were killed, 1,000 were injured, 900 Jewish homes were destroyed, and hundreds of Jewish properties were ransacked.
Baghdad's population is estimated at eight million within the city and approximately 10.5 million across the wider metropolitan region. It is the second largest city in the Arab world after Cairo and the fourth largest metropolitan area in the Middle East after Istanbul.