I left the kingdom I was part of and wanted to start my own kingdom. I assumed that I could just take a castle just like in warband and start my own kingdom, but it did not let me make one. I just assumed that I needed a city so I conquered one instead. But I still couldn't make a kingdom and now I have two cities and one castle but I still can't form a kingdom, therefore, it is not letting me form armies and making me not able to play the game.