His father, Þorsteinn Jónsson, was a falconer at Vörðufell, and his mother was Ásta Loftsdóttir.
According to legend, Loftur tried (and failed) to obtain the legendary grimoire (book of spells) Rauðskinna, which was supposedly buried in 1520 with its author, Bishop Gottskálk grimmi Nikulásson.
Loftur left the Hólar school in 1722 — sources vary as to whether he graduated or was expelled — but what happened in his life after that is uncertain.
[1][2] According to one legend, Loftur was driven insane by his failure to acquire the Rauðskinna and was placed under the care of a priest in Staðarstaður.
The play portrays Loftur as a Faust-like ambitious scholar seeking power and knowledge through sorcery.