thumb|right|[[Frans Floris painted a portrait of his friend Rijckaert Aertsz as St. Luke as a tribute to him, around 1560.]]
Richard Aartsz, or Rijckaert Aertsz (1482 – May 1577) was a Dutch Renaissance painter of historical allegories. Most of his works were painted while he lived in Antwerp. He was a pupil of Jan Mostaert in Haarlem. Frans Floris became his pupil and friend.
Biography
Rykert (or Rijck) was born in Wijk aan Zee, (Beverwijk) and was the son of a fisherman. As a boy he had burned his leg, so he was sent to Haarlem for treatment, but because of an incompetent physician or because it was simply too late, the wound further deteriorated until his leg had to be amputated, which compelled him to walk with a crutch. This is why he was nicknamed Rijk met de Stelt (Rich with the Crutch), which is his now his best known artist name.
During his period of recovery, he often sat near the fire, and drew on the white stone hearth wall with charcoals, which he did so well that his parents asked if he would like to be a painter or draughtsman, and when he responded seriously in the affirmative, he was apprenticed to Jan Mostaert, then a master of a painting workshop in Haarlem. He was able to make a living by painting the "flesh tones" (naeckten can also mean nudes) for other painters in return for a day-wage.