The appearance of portrait miniature is traditionally dated back to the 16th century when the miniature became a portrait genre. The Reformation processes occurring in Europe at the time also influenced the genesis of forms, technique and style of portrait miniatures. This paper focuses on the factors (related to the Reformation) which affected the formation of new images embodied in H. Holbein’s and N. Hilliard’s works. The rise of the portrait miniature as a new type of portrait, its features, and uniqueness of its properties are explained through the study of certain political, social, and cultural aspects of the Reformation movement in the context of English art.