Eagle in the Snow is considered one of the definitive works of historical fiction in the English language. Written in 1970 by Wallace Breem, the novel is set in Britannia and Germania in the late 4th and early 5th Century, and centers around the Roman general Paulinus Maximus, a pagan in an age of Christianization. Maximus and his friend Quintus command the defence of Hadrian's Wall, but when news comes of an impending Germanic invasion across the Rhine, Maximus is promoted to 'General of the West' and reassigned to Moguntiacum, where he and his one legion are tasked with defending the entire border between Germania and Gaul.

As he is carrying out his duties, more and more of his allies—including those who were once his enemies—try to persuade Maximus to seize the Western Emperorship for himself. He is initially reluctant, but after witnessing the depravity and inefficiency of the current government, he decides to assume the throne himself—assuming he can hold back the Germanians.

The character of Maximus is loosely based on the real-life Marcus, who was declared Emperor of the West by his legions in Britannia but was soon executed. The Germanic invasion that Maximus defends against was the real Germanic invasion of Gaul in AD 406.

The characters of Maximus and Quintus provided inspiration for the characters of the same names in the movie Gladiator (2000), and the battles between Maximus' legion and the Germanians at Moguntiacum were the basis for the opening sequence of Gladiator.