Spanish navigation manuals and the English art of navigation

For most of the sixteenth century the books that taught England to navigate were Spanish: Enciso, Pedro de Medina and Martín Cortés in translation, behind them a Casa de Contratación that examined pilots and kept a master chart. The assessment used here is a British naval historian's — Cortés in Richard Eden's version was, on his reading, the most influential book after the Bible in English. The same paper insists the underlying invention was Portuguese and Spanish together.