Decury

In Ancient Rome, a decury (Latin decuria) was a group of ten people, ranged under one chief, or commander, called a decurio. The Roman cavalry was divided into decuries.

Romulus divided the whole Roman people into three tribes; over each of which he appointed a tribune. Each tribe he subdivided into ten centuries, with centurions at their heads. And, each century he subdivided further into ten decuries, over each of which a decurio commanded.