See also: England - Scotland & Ireland - France - Germany - Italy - Scandinavia - Spain - Manuscripts, archives and Special Collections - Newspapers - Rare Books
Several versions of this portrait exist, three of which are believed to be authentic. Of these the version at the Museo Thyssen-Bornemisza is dated 1579.
The Huygens Institute is the national institute for research on history and culture of the Netherlands. Publishes several collections of digital sources and data.