Hagen was an adherent of the group of patricians led by his relatives, the "Overstolzen", and he opposed bitterly both the party of the "Weisen", the despised guilds, and also the archbishops of Cologne, who, as lords of the city, were the natural enemies of the development of Cologne into a free imperial city.
The Reimchronik consists of some 3,000 couplets; as a chronicle it is almost complete, if based at times on unreliable traditions.
After a legendary introduction, permeated with the idea of municipal liberty, it recounts the conflicts between the city of Cologne and the archbishops Conrad and Engelbert II, and the feuds between the patrician party and the guilds in the years 1252–1271.
The 1913 Catholic Encyclopedia describes the Reimchronik as having minimal artistic merit, aside from "some lively descriptions".
According to the encyclopedia, the chronicle is valuable as an unusually complete record of a German city of the period, although sometimes biased by Hagen's patriotism.