Good quiz. According to "http://en.wikipedia.org/wiki/List_of_largest_cities_throughout_history" 2075 BC largest city was Girsu with a footnote "Girsu (Telloh), the later capital of the state of Lagash, was situated 25 km NW of Lagash (Tell al Hiba), though both sites are frequently referred as Lagash." So maybe you should accept Girsu also?
great quiz but agree with previous posters you should loosen up a bit on acceptable answers. I managed to score in the 99th percentile but would have been easier if you accepted the more common spelling Cordoba, and maybe if you accepted Luxor for Thebes (Thebes was the Greek name for the city anyway). Just a few suggestions. Otherwise great quiz, was going to do the same one myself.
Hard quiz with all the ancient cities. 14/26. Can't believe I forgot to guess Cairo and forgot the H in Baghdad. Can you accept Nanjing and Cordoba since you accept the modern name for Constantinople?