Following the clean-lined style of the Neoclassical period came the Historicistic period, lasting from about 1840-1900. Architects travelled all over the world and were inspired by styles from other countries and style periods. Historicistic architecture therefore contains a mixture of elements from many different historical styles.

A window from the Historicistic period can resemble a window from many different eras - a Gothic window, a Baroque window, or a mixture of multiple styles. During the period, industrialisation and new building materials such as cast iron and concrete changed the course of window production and pushed the development of new types of windows. For instance, the cast iron window and the Chicago window.