I'm not sure this is a legitimate claim, but Damascus has been one of the most conquered cities in world histories. Since its inception in 7000 BCE the city has continually existed and changed hands multiple times. Somebody may prove me wrong, but I think it can give any other city "a run for its money." I highly recommend the book "Damascus: A History," by Ross Burns. It goes through the many millenniums of the city's rule. It is my source for many of this information.

Essentially, the city has been conquered from its inception in 7000 BCE to 1941, and not to break the 20 year rule, but it is being fought over to this day.

Specifically, in the time of the crusades, 1140, the city was taken by the ruling sultans, Imad al-Din Zeng,"Mameluke," basically the term for slave soldier, Mu'in al-Din Unur. This "Mameluke" conquered the city, and his former master, Imad al-Din Zeng laid siege to Damascus. Imad al-Din Zeng proved unable to retake the city was soon driven off, but the city was constantly under threat from christian crusaders. When Mu'in al-Din Unur died in 1149, his brother conquered the city. So, for example, in a 10 year period from 1140 to 1150 the city was conquered twice.

My source for this case study is still "Damascus: A History" by Ross Burns.

Going off of the book, and from the internet:

• Original founding, conquering by Hyskos Kingdom in 1750 - 1500 bc,
• Unknown conquerors,
• Egyptian rule starting ~1350 (letters stating their rule),
• Hittites conquer and Egyptians reconquer,
• 1250 BCE,
• Sea Peoples 1200
• Unknown 1200-1100,
• Aram-Damascus gains control 1100 BCE,
• in a civil war "Ezron" captures the city,
• 850, Israel possibly sacks the city,
• 800, Assyria conquers the city,
• 727 city revolts and is reconquered,
• 572 conquered by Babylonian Empire,
• 530~ conquered by Achaemenid Empire,
• 330, conquered by Alexander the Greats empire,
• 323, following Alexanders death, conquered by successor kingdom, Seleucid empire,
• 64 BCE, conquered by Romans,
• 200~CE Damascus conquered in revolt,
• August 634 CE conquered by Umayyad Empire,
• August 750 conquered by Abbasid,
• 751, city revolts and is conquered once more,
• 811, city revolts and is reconquered,
• 878, conquered by Admad ibn Tulun,
• 906 Qamaratins conquer the city,
• Ikshidids take city in 907,
• Fatmids conquer in 970,
• 975, turkish revolt and independence,
• 977, reconquered by Fatmids,
• 998, city declares independence and is reconqured by Fatmids,
• Abu Sa'id Taj ad-Dawla Tutush conquers the city in 1097,
• 1104, conquered by Seljuks,
• 1193, conquered by Abuyyids,
• soon conquered by Mamelukes, 1260,
• conquered by mongols, 1260
• reconquered by Mamelukes 1260,
• conquered by Ottoman Turks in 1516,
• 1832, conquered by Ali Pasha of Egypt,
• 1840, retaken by Ottoman Turks,
• 1918, conquered by French forces,
• June 21 1941, conquered from Vichy France by Free French Forces.

As a general reminder for this question, please look to the rules on what constitutes an acceptable/good answer in /r/AskHistorians

A good answer will go further than a simple short sentence.

Simply naming a city and/or linking to a tertiary source in a one-line answer is not an acceptable answer.