The goal is misleading, you need to have the number of troops stated in the goal (in my case it was 65). So I trained a full army of 65 Phalanxes and Archers since they only cost 1 troop space, which kind of stinks because I want a mix of units and not just a ton of 1 or two types, but I did it to fulfill the goal and get the crowns.
Other units like Horse Raiders (3 troop space) and Cataprhact's (6 troop space) made it impossible to get the goal done since they seemed to be counting actual number of units and not maxing out your troop capacity.