Portret "Onbekende man" op hout door Cornelis Buys meester van Alkmaar, circa 1500

Cornelis Buys's Portret "Onbekende man," painted around 1500 and now at castle Huis Bergh in 's-Heerenberg, is a portrait of an unknown man by a painter from Alkmaar in northern Holland — a significant work because it documents the spread of Flemish portrait conventions into the northern Netherlands at the very beginning of the sixteenth century. Cornelis Buys was the brother of the more famous Jacob Cornelisz. van Oostsanen, and the two painters between them helped establish a distinctive Alkmaar-Amsterdam tradition of panel painting that would eventually feed into the great flowering of Dutch art in the seventeenth century. The portrait of an unknown man — anonymous sitter, anonymous master, provincial location — represents the quiet backbone of early Netherlandish portraiture.

The three-quarter portrait on wood panel follows Flemish conventions with a dark ground and careful attention to the individualization of the sitter's face. The handling of costume — dark fabric, plain collar — is precise and observational. The paint surface has the enamel-like quality of early Netherlandish technique.