Today, it is his poetry for which he is chiefly known. His poems, including the famous "Fri felt" ("Free Fields"; 1905), the "Rugens sange" ("Songs of the Rye"; 1906) and "Heimdal's Wanderings" (1924), reveal his appreciation for the harvest. Because of their lyrical quality, many of these poems were used as settings for songs by various 20th Century Scandinavian composers, such as Carl Nielsen. In these songs he sings of the moors of his region, the areas of his childhood and the poor life in the country, often switching between harsh realism, a fresh love of nature and sentimental nostalgia. Some of his poems are written in dialect. Among his best known are the beloved "Jeg er Havren" ("I am the Oats"); "Jens Vejmand", a tribute to the worn-out roadmender; "Jutland" (English translation by J. A. Peehl); and "Historiens Sang" ("The Song of History"). As a poet, he shows himself an agitator, writing battle songs for the working class.