John De Witt: Grand Pensionary of Holland Twenty Years of a Parliamentary Republic. E-book. Formato PDF M. Antonin Lefevre Pontalis   -  Forgotten Books, 2017  - 

Although some writers have asserted that his education was neglected, he had profited by the pains taken with him by his first tutor, Frederick of Nassau, Lord of Zuylestein, but had never acquired any extensive knowledge of science, letters, or history. The study of languages was the only one that seemed to please him. He spoke equally well Dutch, French, English, and German, and understood Spanish, Italian, and Latin, so that he was able, as he grew up, to maintain in timate relations with the foreign ministers at the Hague. By this means he was initiated into the policy of the different courts of Europe, and acquired in his youth that knowledge of diplomacy which he afterwards turned to such good account. From time to time,' writes Saint Evremond in 1665, we go to pay our respects to the prince, who would have reason to complain of me if I said no more than that rarely has a person of his quality shown such intelligence at his age.'