William I, Prince of Orange (1533-1584). Apologie ou defense de tre illustre Prince Guillaume par la grace de Dieu Prince d'Orange: Conte de Nassau, de Catzenellenbogen, Dietz, Vianden, &c. Leiden: Charles Syvius, 1581.
The title page summarizes the content of this pamphlet: it is William I of Orange's defense, written in French, against the proscription against him issued by the King of Spain, Philip II.