# This is the list

"These are the names"

# commanders of thousands and hundreds

"the commanders of large military divisions and the commanders of smaller military divisions" 

# in various ways

"in different ways" or "in many ways"

# Each military division served month by month throughout the year

This means that each division took turns serving periods of a month at a time.

# Each military division

"Each group"

# throughout the year

"all year long"