ABSTRACT
The crucial role of Colonel Henry Sidney during the 1680s in supporting the claims of the House of Orange and William III to the English throne is often underestimated and merits reassessment. In May 1678 Colonel Sidney, the fourth surviving and youngest son of Robert Sidney, second Earl of Leicester and Dorothy Sidney, Countess of Leicester, led an infantry regiment in the British expeditionary force to Flanders. Henry Sidney’s relationship with William III, Prince of Orange and he became a valuable conduit for diplomatic negotiations between the English and Dutch. Henry Sidney’s distinguished court career during the last quarter of the seventeenth century often interlinked with that of his nephew and coeval Robert Spencer with whom he had grown up as a child. Henry Sidney was simultaneously continuing to court the trust of William III, Prince of Orange, and considered it imperative that William should either personally come to England or declare publicly his claim to the English throne.
