Be last in a line or sequence, as in As a slow walker, I'm used to bringing up the rear, or In test results Tom always brought up the rear. This term almost certainly came from the military but the earliest citation given by the Oxford English Dictionary is from a 1643 religious treatise by Sir Thomas Browne: “My desires onely are . . . to be but the last man, and bring up the Rere in Heaven.”
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.