Renaissance windows are inspired by the ideals of Classical Antiquity: geometry, mathematics, and proportions. The windowpanes are made of crown glass or cylinder glass set in decorative lead lights. Renaissance windows are often decorated with carvings on the casements, transom and mullion and proportioned to fit within the house’s timber-frame.
Around 1350, a lead rolling mill was developed to roll lead into rails. The invention made the production of windowpanes faster and less expensive which meant that windows with glass panes became common in townhouses in 16th century Europe.