Sune Sik,, was allegedly a Swedish prince. According to Olaus Petri, he would have been a younger son of King Sverker I of Sweden and father of Ingrid Ylva. In surviving contemporary documents one Sune Sik can be found who lived much later. That Sune Sik made a donation to Vreta Abbey as late as in 1297. He might have ordered a restoration of a chapel in which he eventually was interred, and later Cistercian tradition may then have turned him into a prince. This has caused some historians to view Olaus Petri's account of him as unreliable.