Rise of Castles: Ice and Fire: I sent my legion to a place on the map to gather resources, but the..

Rise of Castles: Ice and Fire: I sent my legion to a place on the map to gather resources, but the place disapeared from the map and I can't recall my legion. I see that I can research in the legionnaire tree, but that is a long way off. Will my legion return? What can I do? Usually they gather resources and return on their own.