A pace (or double-pace or passus) is a measure of distance used in Ancient Rome. It is nominally the measure of a full stride from the position of the heel when it is raised from the ground to the point the same heel is set down again at the end of the step. Thus, a distance can be "paced off" by counting each time the same heel touches ground, or, in other words, every other step. In Rome, this unit was standardized as two gradūs or five Roman feet (about 1.48 metres or 58.1 English inches). There are 1000 passus in one mille, and a mille was sometimes referred to as a mille passus.
The Byzantine pace or vema (βήμα [ˈvima]) was 2½ feet (pous).[1]
A pace in modern terminology is usually taken as being a single pace rather than a double pace. It has no formal definition but is taken as being around 30 inches.[2]