Bukhara itself as "full of knowledge", referring to the fact that in antiquity, Bukhara was a scientific and scholarship powerhouse. Rumi verifies this when he praises the city as such. Other examples illustrate the eminent status of Khwarezmid and Transoxianian cities in Persian literature in the past 1500 years: The world of hearts is under his power in the same manner that The Khwarazmshahs have brought peace to the world. —Khaqani Shirvani A greedy one went to Khwarezm-shah early one morning, so I have heard —Saadi Yaqut al-Hamawi, who visited Khwarezm and its capital in 1219, wrote: "I have never seen a city more wealthy and beautiful than Gurganj". The city, however, was destroyed during several invasions, in particular when the Mongol army broke the dams of the Amu Darya, which flooded the city. He reports that for every Mongol soldier, four inhabitants of Gurganj were killed. Najmeddin Kubra, the great Sufi master, was among the casualties. The Mongol army that devastated Gurganj was estimated to have been near 80,000 soldiers. The verse below refers to an early previous calamity that fell upon the region: Oh land of Khorasan! God has saved you, from the disaster that befell the land of Gurganj and Kath —Divan of Anvari Notable people The following either hail from Khwarezm, or lived and are buried there: Al-Biruni, outstanding scholar Ma'mun II, Khwarezm Shah and founder of an academy Najm al-Din Kubra, Sufi mystic Rashid al-Din Vatvat, panegyrist and epistolographer Fakhr al-Din Razi Ala al-Din Atsiz, Khwarezm Shah Ala al-Din Muhammad, Khwarezm Shah Jalal ad-Din Menguberdi, Khwarezm Shah Abu l-Hasan Sa'eedeh ibn Sa'deh, commentary writer on the writings of Sibawayh. Abaaq al-Khwarazmi Muhammad ibn Musa al-Khwarizmi, mathematician (for whom the term algorithm is named.) Muhammad ibn Ahmad al-Khwarizmi, 10th century encyclopedist who wrote Mafatih al-'Ulum ("Key to the Sciences"). Zamakhshari, scholar Qutb al-zaman Muhammad ibn Abu-Tahir Marvazi, philosopher Al-Marwazi, astronomer Mahmud Yalavach, ambassador and governor of Mavaraunnahr (1224–1238) Abu l-Ghazi Bahadur, Khan and historian See also Eurasian Avars, alliance of Eurasian nomads (6th–9th century AD) Karakalpakstan, autonomous republic within Uzbekistan Keraites, 12th-century Turco-Mongol tribal confederation Khorezm People's Soviet Republic (1920–1923/25) Khwarezmian language, extinct East Iranian language Koi Krylgan Kala, archaeological site; Khwarezmian settlement (c. 400 BCE – c. 400 AD) Mount Imeon, Hellenistic name for Hindu Kush, Pamir and Tian Shan mountains Uar, tribal confederation linked to the Huns (5th–8th century AD) Zoroaster (c. 1500–1000 BC),