Convert from pace [Roman] to twain

Unit Definition (pace [Roman])
A pace (or double-pace) is a measure of distance used by Ancient Rome. It is the measure of a full stride from the position of the heel when it is raised from the ground to the point he heel is set down again at the end of the step. In Rome this was standardized as about five Roman feet or 58.1 English inches.

Unit Definition (twain)
The twain is an old word for the number two, derived from the Anglo-Saxon twegen. The American author Samuel Clemens (1835-1910), who had been a riverboat pilot on the Mississippi in his youth, took his literary name from a traditional riverboat phrase "mark twain", meaning "exactly two" fathoms of water. This was the minimum depth needed for the boats to operate safely without running aground.