Complex sentence: He was skilled both as a miniaturist and a painter of monumental works, and seems to have had knowledge of metal work, given his realistic depictions of objects such as the Magi's gifts in the Cologne altarpiece.
Split into simpler sentences: He was skilled both as a miniaturist and a painter of monumental works. He seems to have had knowledge of metal work, given his realistic depictions of objects such as the Magi's gifts in the Cologne altarpiece.