Fixed frame window

Fixed wooden windows without opening fittings became common in the Viking Era, ca. 800-1050. Translucent materials such as animal hide and bull's horn were used to cover the early windows. Bullhorn windows, as they are also called in Danish, were made from the 10-12 cm (3-4 inches) at the horn's base. The horn was cut lengthwise, boiled and flattened into a pane, which was then put into a press, and finally oiled. In southern Europe, alabaster and marble panes were also used in windows.