Leslie Stephen,
Dictionary of National Biography…
(1900)
“ William Henry entered the Dutch cavalry in 1672, but as a young man appears to have been best known at The Hague for his gallantry and his good looks, and as a companion of the prince's pleasures. He was greatly trusted by William, and acquitted himself so well on a mission of observation to England in August 1687, the nominal purpose being to condole with the queen-consort upon the death of her mother, the Dowager Duchess Laura of Modena, that he was named envoy upon a much more important occasion in the summer of the following year. ”
