Jan van Eyck

Jan van Eyck (c. 1385 – 9 July 1441) was a Flemish painter, one of the first artists to explore oil paint and one of the first to use the 3/4 pose.

Sourced:

 * AlC IXH XAN (Als Ich Kan)
 * I do as I can
 * The inscription on the frame of Man in the Red Turban.