Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: The historical evidence suggests that Lochner's paintings were well known and widely copied during his lifetime, and remained so until the 16th century. Early examples in ink after his Virgin in Adoration are in the British Museum and École nationale supérieure des Beaux-Arts. The influence of Lochner's Last Judgement can be seen in Hans Memling's Gdansk altarpiece, where the gates of Heaven are similar, as is the rendering of the blessed. Albrecht Dürer knew of him before his stay in Cologne, and Van der Weyden saw his paintings during his travel to Italy. The latter's Altar of Saint John is similar to Lochner's Flaying of Bartholomew, especially in the executioner's pose, while his Saint Columba altarpiece includes two motifs from Lochner's Adoration of the Magi triptych; specifically, the king in the central panel with his back to the viewer, and the girl in the right hand wing holding a basket containing doves.The Heisterbach Altarpiece, a dismantled double set of wings now broken apart and divided between Bamberg and Cologne, is heavily indebted to Lochner's style. The inner panels show sixteen scenes from the lives of Christ and the Virgin that bear multiple similarities to Lochner's work, including in format, compositional motifs, physiognomy and colourisation. The work was for a period attributed to Lochner but is now generally accepted as bearing his strong influence. In 1954 Alfred Stange described the Master of the Heisterbach Altarpiece as Lochner's "best-known and most important pupil and follower", although research in 2014 indicates that the two may have collaborated on the panels.Research in 2014 by Iris Schaeffer into the underdrawings of the Dombild Altarpiece established two guiding hands, presumably Lochner and an exceptionally talented pupil, whom she concludes was in probability the principal artist behind the Heisterbach Altarpiece. A counter view is that Lochner's workshop was producing to a deadline, and he delegated as a matter of expediency.
What was the name of the person that Albrecht Dürer knew of before his stay in Cologne?