He's been called a master realist, the first postmodernist, history's greatest portraitist.
In the words of French artist Edouard Manet, Diego Rodriguez de Silva y Velazquez was "le peintre des peintres" - the painter's painter.
"Velazquez is perhaps the very greatest painter, a painter who was in tune with his medium - the stuff of paint," said Dawson Carr, curator of a major exhibition of the artist's work that opened Wednesday at the National Gallery in London.
The gallery holds nine works by the Spanish master, who lived from 1599 to 1660 - more than any institution apart from the Prado museum in Madrid.
The Prado has loaned eight works to the show, which contains 46 paintings spanning Velazquez's career, from tavern scenes he painted as a teenager to a sombre late portrait of his royal patron, King Philip IV.
"The exhibition is Velazquez's work as a whole, but based around our own collection," said National Gallery director Charles Saumarez Smith.
The National Gallery says it has sold more advance tickets for Velazquez - 13,000 - than for any other show in its history. It's the latest blockbuster in a season of big visual arts exhibitions in London, whose highlights include a David Hockney retrospective at the National Portrait Gallery and a large Hans Holbein exhibition at Tate Britain.
The National Gallery show reveals Velazquez's extraordinary eye for detail - and the amazing economy he used to capture it. A picture of an old woman cooking eggs in an earthenware bowl, painted while Velazquez was still a teenager, captures with a few brushstrokes the moment the egg white turns from translucent to solid.
He applied the same grasp of everyday detail to religious and mythological scenes. In "Kitchen Scene with Christ in the House of Martha and Mary," the figures are glimpsed in a corner of the painting, through a window. In the foreground is the kitchen where two servants work at a table laid with garlic, fish and eggs. In "The Adoration of the Magi," the Virgin Mary is depicted as a simple girl who might have come from his native Seville. "He finds purity in something most people can identify with," Carr said.
Carr said Velazquez spent his early career painting "humble subjects - ordinary people doing ordinary things." "He is declaring himself from the beginning to be a realist. Velazquez's talent allowed him to follow un-idealized nature and use it as the center of his art."
It's a philosophy that Velazquez took to Madrid, where, at 24, he became a court painter to Philip IV.
Many of the show's later works are portraits of the king and his family - and even here, Velazquez's realism and his genre-bending are striking.
In "Prince Baltasar Carlos in the Riding School," the young crown prince exercises his horse in front of the royal palace. Grooms and servants swarm in the foreground, while the king and his queen are glimpsed in the background.
It is, Carr said, classic Velazquez _ "a casual moment in the life of the court."
"There are many centres of focus."
The exhibition does not contain the greatest example of this approach, Velazquez's masterpiece "Las Meninas." Completed in 1656, it is a portrait-in-progress of the young Infanta Margarita, surrounded by ladies-in-waiting, a dwarf, a dog and even the artist himself _ the king and queen visible as reflected mirror images in the background. The painting is a centrepiece of the Prado's collection and, Carr said, unloanable.
But the exhibition contains plenty of other masterpieces, including "The Toilet of Venus," a majestic reclining nude of the Greek goddess of love which is part of the National Gallery's permanent collection.
The final room of the show contains a late portrait from 1656 of a pale, jowly Philip, eroded by care and the loss of his first wife and eldest son.
"There is no longer any way to hide the fact that the king has been worn down by the loss of empire and the loss of family," Carr said.
He said the Spanish king deserves credit for allowing Velazquez' talent to flourish.
"He had a patron who understood him and understood his genius, and not all would have done."
"Velazquez" runs at Britain's National Gallery until January 21, 2007, and will not travel.