Can't build monument? pre - astrology

[bahamuto]

So I was playing as malinese empire and I was at war with the German's. So I have some monuments build and and also am building one in their captured city. All of a sudden I get a message saying I can no longer build a monument in the city and from that point forward I can not build a monument.

I also am no where near astrology, so I got really confused. Is there something else I"m missing about monuments? Thanks for any information you can provide.

 

[slaze]

maybe you conquered stonehenge

 

[f35acepilot]

Did you build or capture the city with Stonehenge? (which gives you free monuments in all of you cities)

 

[bigmac44]

Perhaps you captured stonehenge on the previous turn.

 

[bahamuto]

Never thought about that.... That's probably what happened.

 

[0range]

They probably made Stonehenge