The term muster designates the process or event for the of accounting for members in a military unit. Within the United States Army Reserve, it is an annual event used for screening purposes.[1]
In Tudor England, musters were periodic assessments of the availability of local militia to act as a defence force when needed.[2] To some extent, the system was an outdated remnant of the feudal system where local lords had their own armies, which they provided for the King as required.
This practice of inspections led to the coining of the English idiom pass muster, meaning being sufficient.