The Lost Legion

From Author Wars - https://authorwars.com/publications/the-lost-legion-273219.html

Overview:

Title: The Lost Legion
Author: H. Warner Munn
Year: 1980
ISBN-10: 0385148283
Publisher: Doubleday
Price: $14.95
Pages: 621
Binding: Hardcover
Type: Novel
Title Reference: The Lost Legion
Notes: Historical Fiction (non-genre).
Info from Locus #230 (February 1980). Cover artist on back flap in Fantlab photo; also on back flap of Archive.org copy.