Paintings such as A Pair of Lovers in a Landscape, c.1643, and The Rape of Europa from the early 1650s, are exercises for connoisseurs. They are rich in both classical allusions — temples, grottoes, references to Ovid — and a pervasive eroticism. Walpole captured their mood perfectly: "His nymphs trail fringes and embroidery through meadows and purling streams." His pictures of musicians such as A Man Playing a Pipe, c.1648, are a direct reference to his Netherlandish roots and the work of the Utrecht painters Hendrick ter Brugghen and Gerrit von Honthorst. In The Concert, c.1650, he combined both themes: it is an allegory of love and music in which he included a self-portrait as the viol player surrounded by musicians and court beauties in various states of undress. 

The most beautiful of all, though, is Nymphs by a Fountain, c.1654, in which five exhausted women sleep hugger-mugger in a Gainsboroughesque landscape. In their different poses Lely managed to show the nude in 360 degrees. The picture, a ravishing image of sensual lassitude, was owned by Dulwich College where the masters kept it under lock and key "for fear it should injure the morals of the boys". It might have too. 

Lely clearly understood that difficult times called for alluring pastorals and painted some 35 such subject pictures: the fact that he produced several versions of some of them is evidence that they had an appreciative audience, one that this excellent exhibition will resuscitate. 

The Stuart dynasty is also the focus of the exhibition at the National Portrait Gallery, in this instance Henry, Prince of Wales, the eldest son of James I, who, had he lived, would have been king rather than his hapless brother Charles I. Henry, handsome, intelligent and cultured — a true Renaissance prince — was the first male heir apparent in England for more than 50 years and was the great hope for Protestantism. His promise did not reach fruition: he died aged 18 in 1612 leaving his countrymen "passionately bewailing so great a losse". 

The Lost Prince brings together not just paintings and drawings of Henry by the likes of Nicholas Hilliard, Isaac Oliver and Robert Peake but artefacts associated with him including armour, masque designs by Inigo Jones and poems by Ben Jonson in his own hand. They are the remains of a short-lived golden age of patronage and as well as numbering objects of real beauty are a testament to one of English history's great what might have beens.