The term 'body of troops in close formation' can be summarized as a phalanx. A phalanx is an ancient Greek military formation consisting of a dense mass of infantry soldiers standing shoulder to shoulder in a rectangular formation, with their shields overlapping and spears pointing forward. This formation was used to create a wall of protection against enemy forces. The phalanx was a very effective tactic in ancient warfare, and it was used by many different civilizations throughout history.