During my last attack I happened to notice it had said "I had not won the city" and I was wondering what this had meant and how I do "win the city" Thanks a lot.
It depends what you were attacking. If you were attacking a fort, You must attack it and win 3 times within a short time frame. If you were attacking an oasis, You just need to attack it once and win. And if you were attacking a city, You need to attack it ten times and win within a short tine frame. You can only take over sub cities. And in order to capture any of these, you would need a spare slot for whatever you were attacking.
If your city/oasis/for slots are full then you cannot take it. Also, forts and branch cities take more than 1 victory over the city. Forts take 3 wins, oasis take 1, and branch cities take 10.