550 may well be possible, if not 500 or sub-500 with a high domination limit.
Yep 550 is definately possible, infact 540AD which I have had accepted.
3200BC SGL for Masonry (my only SGL)
by 2030BC I was 2 turns of Philosophy
in 1000BC I had 40 Cities, 5 settlers and 54 workers
here is a screenshot of my kingdom at 1125BC
Temple of Artemis was hand built in 850BC and Statue of Zeus in 775BC
Though I never used an AC in anger
On reaching the Middle Ages I went for Engineering which I sel researched, then I gifted up two of my three scientific opponents getting feudalism and monotheism which allowed me to enter feudalism in 490BC
At this point I had 101 cities at this point I had 6 luxuries (one of which I had culturally aquired right next to a Babylonian city) 15 settlers and 106 workers.
I then reseached to Gunpowder and then Theology,
By 230 BC I had 4 turns left on the hanging gardens, 5 turns left on theology, 144 cities, 8 settlers and 129 workers, I had 7944 culture at 542 per turn.
The hanging gardens was completed in 170BC and I had 20 turns left on a sistine chapel pre-build with theology just two turns away.
In 10BC I had 16777 culture and was gaining at 948 per turn, I also had all luxuries hooked up, 158 cities 3 settlers and 132 workers.
Sistines chapel was built in 170AD.
By 250AD I had 166 cities and 134 workers, with 31713 culture and 1389 per turn.
Eventulally I built 4 more cities and acquired 2 in culture flips and ended in 540AD within 57 tiles of a dominationlimit of 1038, with 1774 culture per turn finishing on 80268 culture.
EDIt : I abbandoned my marketplace statergy for this game and only built two or 3 (one which should have been towards a colosseum but I didnt change it by mistake, I also acquied a longbow this way)
