In ancient Greece, a phratry (phratria, Greek:φ(ρ)ατρία, "brotherhood", "kinfolk", derived from φρατήρ meaning "brother") was a social division of the Greek tribe (phyle). The nature of these phratries is, in the words of one historian, "the darkest problem among the [Greek] social institutions." Little is known about the role they played in Greek social life, but they existed from the Greek Dark Ages until the 2nd century BC; Homer refers to them several times, in passages that appear to describe the social environment of his times.