The first English translation of Castiglione's The Courtier was published in 1561. Thomas Hoby's English translation (from its original Italian) is often used to this day and can be found in its entirety on Google Books. Then eleven years later, England saw its first translation of this courtly etiquette book into the lingua franca of the court, Latin. It is this 1572 Latin edition of The Courtier that Edward de Vere became involved with.
Think of The Courtier as a sort of answer to Machiavelli's The Prince – an austere, dark treatise on how to succeed in politics. The book offers Castiglione's comments on a similar subject matter presenting an alternate, more altruistic approach to court behavior. There can be little doubt that Edward de Vere was responsible for the publication, as he himself composed the introduction to the translation by a man named Bartholomew Clerke. While most Elizabethan writers/patrons crafted brief introductions of a few sentences, Edward de Vere wrote lengthy, gorgeously written piece which honors not only Castiglione but Clerke, too.