In the king's eldest boy, _Baltazar Carlos_, who was born in 1629, Velasquez found a model for two or three of his most charming pictures. One is at Castle Howard; a second the equestrian portrait, on a galloping pony, at the Prado; and a third the full length hunting portrait, also at the Prado, in which we see the little prince standing under a tree, gun in hand, with an enormous dog lying beside him. Another is at Vienna, representing him as of about eleven years old, full length, with his hand resting on the back of a chair. All of these owe some of their charm to the youth and attractive personality of the subject; but if we want to see the power of Velasquez without any outside element to help us to appreciate it, there is the portrait of the sculptor _Martinez Montanes_ at the Prado. "The head is wonderful in its colour and its modelling," writes Senor Beruete; "and what a lesson in technique! The eyes, lightly touched with colour, are set deep in their sockets, and surmounted by a strongly marked forehead. The high lights are of a rich _impasto_, manipulated with extraordinary skill; the greyer tones of the flesh, so true and so delicate, are painted in a way that brings out with marvellous truth, both the soft parts of the cheeks and the harder structure of the face, under which one can follow the bones of the nose and forehead.... Everything in the picture is spontaneous, and one can see that it is a pledge of friendship given by one artist to another; there is nothing here of that artificial arrangement that spoils commissioned portraits even when they are the work of a painter as independent as Velasquez was. One feels here the assurance of an artist who knows that his work will be understood by his friend in the spirit in which it was executed." M. Lefort, the French critic, is even more enthusiastic. "Ah! these redoubtable neighbours," he exclaims, seeing it surrounded by the works of other painters at the Prado. "This canvas makes them look like mere imitations--dead conventional likenesses. Van Dyck is dull, Rubens oily, Tintoret yellow; it is Velasquez alone who can give us the illusion of life in all its fulness!" In 1649 Velasquez paid his second visit to Rome, where he painted the famous portrait of His Holiness, _Pope Innocent X._ which is now in the Doria palace. This is exceptional in treatment, inasmuch as it is the only portrait by Velasquez in which the subject is seated--excepting of course equestrian portraits--and instead of the usual quiet tones of grey and brown which he was so fond of employing, the picture of the Pope is a radiant harmony of rose red and white. In its realism it is even more surprising than most of the other portraits, considering how ugly the face had to be made to resemble nature, although the sitter was of a still higher rank than Velasquez's royal master.