Death according to ''Erik's Chronicle''
According to '' Erik's Chronicle'', after being away for nine years, Jon Jarl was killed on his farm at Askanäs on Ekerö by Karelian or Russian pirates the same night that he returned from a crusade between Ingrians and Russians. The ''Chronicle'' states: :''Thz er swa sant som jak her læss'' :''Jon jerl ward dræpin i askaness'' Jon's wife fled across the bay to Hundhamra (i.e. Norsborg), and gathered a mob to kill the perpetrators. They caught up and fought them off at "Eesta skär" (i.e. {{ill, Estbröte, sv, Estbröte, a high islet in the fairway between Ekerö and {{ill, Johannesdal, sv, Johannesdal, in the southwest of Stockholm). How accurately the chronicle reproduces the actual sequence of events is unclear.{{Citation needed, date=March 2023Tombstone
No historical evidence on the jarl exists, although he may be the "Johannes Dux" who is shown on an undated tombstone also labelled "Terror of the heathens"References
{{Reflist {{DEFAULTSORT:Jarl, Jon 12th-century Swedish nobility 13th-century Swedish people 12th-century births 13th-century deaths Date of birth unknown Swedish jarls {{Sweden-bio-stub