Poseidon's Hetairoi are strong against buildings.

The nobility of Macedon prior to Philip and Alexander were the patriarchal heads of tribes and estates called the Hetairoi. They prided themselves on their horsemanship and made up one of the elite units in the Macedonian army, the king’s Companions. Without the benefit of a stirrup, these mounted spearmen were still very effective in battle. Alexander personally lead his Companions in several critical charges that won battles during his epic march of world conquest.