A full-length portrait to left, facing to right on a rearing white horse. Prince William of Orange (as he then was) wears a buff coat which is perhaps of leather, embroidered with gold and lined with pink silk. A black hat with a white feather surmounts a black full-bottomed wig and his legs are encased in black boots. Around his waist is a heavily gold-fringed red sash and he wears the ribbon and Star of the Garter. The horse is wearing a blue shabracque, or blanket, with the Orange arms in gold, and stands on a rise in the land looking over towards Torbay. The portrait dominates an image showing William's landing in Torbay on 5 November 1688 with 14,000 troops for the invasion of England. In the background is the Anglo-Dutch fleet, with ships on the far left at anchor flying the Dutch flag. Boats with men are coming ashore near Brixham and horses are swimming ashore onto the shelving beach, having been put over the sides of the ships to land this way. The figures of men and horses on the beach on the left show them being taken in hand.

The son of Charles I's daughter Mary, Prince William of Orange (1650-1702) had married his cousin, also called Mary, daughter of James, Duke of York, in 1677. James had then already converted to Roman Catholicism, which produced a series of political crises after he succeeded to the throne as James II on the death of his elder brother, Charles II, in 1685. These eventually led to a cabal of powerful English Protestant figures inviting William to usurp the British throne, based on the right of succession of his wife, Mary. Although initially unwilling to do so, the threat to the Protestant Netherlands from Louis XIV of France provided a strong incentive for William to accept. He thereby secured Britain as a close ally, rather than as a divided neighbour at best through James's French sympathies. In 1688 he agreed and on 5 November landed unopposed at Brixham, Torbay. He was welcomed in south-west England - which had suffered the retribution of James's 'Bloody Assize' following the defeat of the Duke of Monmouth's rebellion at Sedgemoor, Somerset, in 1685 - and was only briefly resisted by a few of James's Irish Catholic troops at Reading, west of London. These were routed when the citizens of Reading also turned on them and William arrived at St James's, London, on 18 December 1688. On James II's flight (which he abetted) William refused to accept the throne by right of conquest. On his assumption of executive power he and Princess Mary were made jointly king and queen by declaration of right, drawn up by committee of the Convention Parliament, and were crowned on 11 April 1689. It is the only example in modern British history of a joint monarchy, in which William took precedence when in England and Mary (d. 1694) ruled in her own superior right by birth during his frequent absence in the Netherlands. Although William was never personally popular, his reign became symbolic of the Protestant succession, the revolutionary Act of Settlement of 1701 and resistance to French domination in Europe. He was also highly intelligent, well-educated and an able statesman of European reputation. Dutch influences which followed him to England - especially in finance and civil engineering - made his reign one of considerable practical advance, as well as re-forging Anglo-Dutch links after the three Anglo-Dutch wars of 1652-74.

The painting is dominated by the image of William astride his white horse, although he is not thought to have owned a white horse - his death in 1702 resulting from a fall from the roan he usually seems to have ridden. White horses symbolize the heavens, justice and holiness endowed with sacred status. In this context, white is used to signify kingship. The bay can be seen below the belly of the horse and the positioning of the rider symbolizes his domination over the kingdom, reinforced by the boot and spur. He is intentionally out of scale with the rest of the painting, the figures in the background and shipping in the bay, to make the point that this is a statement about domination.

The Dutch artist was son of the marine, landscape and subject painter Thomas Wyck (1616-82) and came with him to settle in England in 1660. Jan specialized in hunting and battle scenes, and there are a number of the latter featuring King William at Blenheim Palace. He was also celebrated for his equestrian portraits, this well-known example being inscribed 'J Wyck Ao 1688'.