# Gregory VII.'s Letter to the German Princes concerning the Penance of Henry IV. at Canossa
**Wikidata**: [Q124695616](https://www.wikidata.org/wiki/Q124695616)  
**Source**: https://4ort.xyz/entity/gregory-vii-s-letter-to-the-german-princes-concerning-the-penance-of-henry-iv-at-canossa