SPANISH LESSONS.

Pablo Picasso is having a tough summer in Madrid. He can handle it, though with nothing like his usual insolent panache--you can feel him sweat. The occasion--"Picasso: Tradition and Avant-Garde," a double exhibition at the glorious Prado and at the Reina Sofia, the desultory national modern-art museum--is purely celebratory in intent, marking the twenty-fifth anniversary of the patriation of "Guernica," after, at the artist's behest, it had waited out in New York the dictatorship of Francisco Franco. The mood is implicitly nationalist, embracing a man who, in 1936, was named the director of the Prado, in absentia, by the republican government, but who never lived in his native land after 1904. (He liked to boast, "All these artists finally belonged to me.") The shows just happen to put Picasso's greatness to severe, vivid tests. By general agreement, he was the best artist of the twentieth century. How good was that? His sheer significance, as the god of modernity in painting, has always beggared ultimate judgment. Now the issue is being forced, at the Prado and the Reina Sofia, by direct comparisons of his work with that of the Old Masters who, from time to time, were important to him, either as models or as goads--notably Velazquez and Goya. The results probe Picasso's artistic weaknesses--he had some--and give focus to doubts about the quality of the monumental egotist's one major painted political statement, created in response to the German bombing of a Basque town, in 1937.

At the Prado, a compact retrospective of about forty borrowed Picassos, in chronological array--from precocious sketches, after Velazquez, that he made at the museum in 1897-98, while still a teen-ager, to a bravura canvas, "Musketeer and Love," from 1969, four years before his death--are interspersed with germane works from the museum's incredible permanent collection. "La Vie" (1903) and "Boy Leading a Horse" (1906) grapple with El Grecos, and "Self-Portrait with Palette" (1906) and two Cubist portraits face off against a Poussin and a Ribera. The determinedly ugly "The Serenade" (1942)--a contorted musician plays for a grotesque reclining nude--confronts one of its likely Renaissance inspirations (or targets), Titian's gorgeous "Venus and the Organ Player." The selection of Picassos is strong but might have been made stronger, with, say, "Portrait of Gertrude Stein" (1906) and "Harlequin" (1915), in place of lesser works. As it is, Velazquez's "The Triumph of Bacchus" (a sly young god attended by tipsy guys you would recognize in the first low-end bar down your street) runs rings around Picasso's classicizing portrait of his son Paulo as a Harlequin (1924) and even the great "Three Musicians" (1921), whose deftly interlocking planes suddenly seem so much empty trickery. Seen through an archway into the museum's main hall, "Las Meninas" craves congress with "Les Demoiselles d'Avignon" (1907), but, instead, the greatest of paintings must abide Picasso's Velazquez pastiches of 1957--bagatalles in which he seems less an arch parodist than an abject buffoon. Other Old Masters on hand include Rubens (his copy of Titian's "Rape of Europa," which amounts to a collaboration that is beautiful beyond measure), Veronese, Zurbaran, and Goya ("The Naked Maja").

The Reina Sofia concentrates on "Guernica," which has resided immovably at the museum since 1992, supplementing it with related drawings, and with two of its three most formidable rivals (David's "Death of Marat" is the missing third) as paintings of political violence--Goya's "The Third of May 1808 in Madrid: The Executions on Principe Pio" (1814), from the Prado, and Manet's "The Execution of Emperor Maximilian" (1868-69), the complete version, from Mannheim.

Mano a mano, Picasso stands up brilliantly to Ribera, Zurbaran, and Poussin, suggesting that the attention to stark fact in the first two, and the rational method of the third, were historic steps in Picasso's direction. The proximity of blue- and pink-period pictures to El Greco's grandiose "Trinity" confirms a familial affinity that is often ...