Turn 110 / 980 AD and all those Admiral are from the Medieval Era, and that's all 4 out of 4 from Medieval Era. So you are playing at Quick Speed, and the global era is still at Medieval (with 0 to 25 turns left).
The cost of each Great Admiral was set to 120 points each with no overprice, so that player needed at least 480 points. It can be done with 8 Great Admiral points per turn for 60 turns, which is achievable with 4 × Royal Navy Dockyard, or even just with 3 with a Lighthouse. The number don't seem extravagant, even less with Pingala with Grants. A Capital with RNDY + Lighthouse generates 6 Great Admiral points per turn and will have those 480 points in 80 turns (out of 110).
England really like those RNDY at half price which offer double Admiral points. It stacks fast.
If you have access to the Great Admiral history, I am pretty sure someone recruited Artemisia the turn before. This is what I think happened:
- England player refused a Great Admiral. Either that England player refused by error, or had a plan, or has been mislead by Elizabeth's ability and tried to save points for a Renaissance one in order to trigger those +2 Trade Routes, or just dislike Artemisia.
- All other players either didn't built an Harbor, or couldn't (England was pillaging or preventing Portugal to set them). So Artemisia took time to find someone who want her.
- Meanwhile, England stacks those Great Admiral point, up to 480 or even more.
- Once a player get Artemisia, England can recruit as many Admiral the points stacked allows to.
Edit: I made a mistake. I said you need 120 points per Great Admiral. It is true for Standard speed. On Quick Speed, it is 80 points I believe. It reduces the points needed from 480 to 320. 2 × Navy Dockyard are able to generate it in 80 turns. So 50-55 with a Lighthouse on top. Making it even more likely.