Reineke, that unknown German Romantic, remembered today only for his phenomenal Undine Sonata for flute and piano, wrote a few slightly clunky symphonies (along with a tons of other stuff). The style is basically Mendelssohn with middle-aged spread. He was not a musical innovator, but a pillar of the establishment. His hometown was on the German-Danish border, and changed hands several times during his life.
The third symphony, in G minor, however inspired a thoroughgoing Dane, Carl Nielsen, in his first symphony of the same key. Nielsen was definitely a musical innovator, with an idiosyncratic style that took him to almost to atonality in the course of his career.
Themes of the two first movements are very similar - declamations based on the first three notes of the scale (G, A, Bb, G, Bb...), which for Reineke is the main theme, and for Nielsen, a later theme that intrudes more and more as the movement goes, totally dominating the last couple of minutes. But the works are very different – Reineke's rather staid, with the punch of a sixty-year-old boxer, Nielsen's burtsing with the youthful vigour of a rising star and full of interesting harmonic juxtapositions (G minor-C major, for example, in the opening chords).
Actually, I misled you just now. Oddly enough, the influence, if there was any, went completely the other way. Reineke wrote his symphony in the late 1890s only a decade before his death and several years after the premiere of Nielsen's 1st!