Thanks for the reponses so far guys 
Another little question - When using supporting units like Battering Ram or Siege Tower, is it the Unit in Escort Formation that receives the benefits the supporting units offer when adjacent to a city, or does anyone attacking the city receive it?

Another little question - When using supporting units like Battering Ram or Siege Tower, is it the Unit in Escort Formation that receives the benefits the supporting units offer when adjacent to a city, or does anyone attacking the city receive it?