Didrik Slagheck (died 24 January 1522) was a Danish archbishop, military commander during the Swedish War of Liberation, and often pointed out as an active participant in the Stockholm Bloodbath. Slagheck was the illegitimate son of a Westphalian priest and appears to have been working in the papal office during his early life. He arrived in Norway in 1510 and soon received appreciation for his service from both Christian II of Denmark and his advisor, Sigbrit Willoms. After some time abroad he returned to Scandinavia in 1517, as assistant to the papal representative Arcimboldi. Arcimboldus is said to have received bribes from Sten Sture the Younger, regent of Sweden, something which Slagheck reported to the king. He was soon sent to Rome to report about Arcimboldus' activities.