|King of Denmark|
|Reign||900's (perhaps early 930's)|
|Predecessor||Gyrd and Gnupa|
|Successor||Harthacnut I ?|
|Born||9th or 10th century|
|Dynasty||House of Olaf|
Sigtrygg was son of Gnupa and the Danish noblewoman Asfrid. According to Adam, he became a Danish king during the tenure of Archbishop Hoger of Bremen (909–915/7). He is remembered on the two Sigtrygg Runestones found near Schleswig, (DR2 and DR4), erected by his mother after his death, suggesting this area represented the power-base of the family.
Based on the testimony of king Sweyn, Adam reports that prior to Hoger's death, Harthacnut came to Denmark and immediately deposed the young king Sigtrygg. However other sources show a Chnuba (usually identified with Gnupa, Sigtrygg's father) still ruling in 934, while Heimskringla reports Gnupa's defeat by Gorm the Old, again placing his death later than Adam would have it. Gesta Wulinensis ecclesiae pontificum tells that Gnupa outlived his son Sigtrygg. Adam himself mentions the existence of other kings at this time and expresses doubt that Denmark represented a single united realm.
- Asfriþr karþi kumbl þaun aft Siktriku sun sin aui Knubu (Asfrith carved this gravestone after Sigtrygg, her son and Gnupa's); Ui Asfriþr karþi kubl þausi tutir Uþinkars aft Sitriuk kununt sun sin auk Knubu (Holy Asfrith carved this gravestone, Odinkar's daughter, after Sigtrygg, king, her son and Gnupa's). A. V. Storm, "Pages of Early Danish History, from the Runic Monuments of Sleswick and Jutland", The Saga=Book of the Viking club, vol. 2, pp. 328–347.