Art historian and critic known for his elegant investigations of Renaissance paintings
Leo Steinberg, who has died aged 90, was one of the most brilliant and original art historians of his generation. He wrote as persuasively about the great Renaissance masters as he did about Jasper Johns and Robert Rauschenberg. His best-known work was The Sexuality of Christ in Renaissance Art and in Modern Oblivion (1983).
I was lucky enough to meet Leo in 1955, and over the decades we continued to see each other – in New York, where he lived for most of his adult life, or on his visits to London. He was impatient of small talk or gossip; conversation was always about particular works of art, which he would discuss intensely. What he said was charged with a sense that art was of overwhelming importance: "anything anyone can do, painting does better".
That passionate involvement with a specific work, and the intelligence which fed it, made him not only an engrossing interlocutor but also a dazzling lecturer (at the Metropolitan Museum of Art, in New York, tickets for his lectures sold out on the day they went on sale). He was invited to deliver the prestigious Mellon lectures at the National Gallery in Washington DC (1982) and the Charles Eliot Norton lectures at Harvard University (1995-96).
He was a devoted teacher, concerned about his students, whose careers he followed. From 1961 to 1975, he was professor of art history at Hunter College, in New York, and then moved to the University of Pennsylvania, where he was Benjamin Franklin professor until his retirement in 1991.
Though firmly identified with the New York art scene, Leo was born in Moscow, where his father, Isaac, a distinguished lawyer, was briefly Lenin's minister of justice. Isaac's radical views (he wanted to shut down all prisons) soon led to his dismissal and emigration to Berlin after threats of assassination.
Leo's childhood in Berlin left him with a barely noticeable German inflection to the otherwise impeccable English formed in his adolescence, since the arrival of the Nazis forced another displacement – to London. There, he finished his schooling and studied sculpture at the Slade. He moved to New York with his family soon after the end of the second world war.
In New York, he worked as a freelance writer and translator, studied philosophy and taught life drawing at Parsons school of art. He embarked on a doctoral thesis at the Institute of Fine Arts at New York University. His study of the diminutive and intricate Roman baroque church of San Carlo alle Quattro Fontane, designed by Francesco Borromini, set out the formal devices employed by the architect to engage the passerby's unsuspecting attention.
While working on his thesis, Leo published criticism in arts magazines and became the most articulate spokesman of the rising New York School of painters. His early advocacy of Rauschenberg and Johns was committed but jargon-free, and he was one of the few critic-historians whose essays were eagerly read by artists for their clarity and elegance. His criticism was collected in a book of essays, Other Criteria: Confrontations with 20th-Century Art, in 1972.
But for all this involvement, he was not really acquisitive and lived rather frugally. In 2002, he donated his collection of 3,200 prints (mostly from the 16th and 17th centuries, but also works by Picasso and Matisse) to the museum of art at the University of Texas in Austin. In 1986 he was awarded a MacArthur fellowship (known as the "genius" grant).
He continued to be prolific, writing with equal enthusiasm about Pontormo and Picasso. The examination of a work was never approached on merely formal terms – although he was a painstaking analyst, always meticulous in his attention to detail, to the way brushwork was used to fragment or to mould space; he would even investigate the implications of words pasted on the printed scraps of collages (treated as abstract patterns by most art historians) in his search for clues to the artist's intention.
Leo was impatient with any criticism which merely analysed the object presented to the spectator, since what really interested him was why the artist had wanted to do it in the first place. This is the key to The Sexuality of Christ in Renaissance Art and in Modern Oblivion. The book is concerned with what Leo termed "ostentatio genitalium", the display of the genitals which often figured in devotional paintings or engravings of the Renaissance and which had been "tactfully overlooked for half a millennium". He argued that the prominence of Christ's genitals was a presentation of incarnational theology explicit in the sermons and pious literature of the time, in which the blood shed at the circumcision is considered the first offering of the redemptive sacrifice.
It was the embodying of an idea which historians, oscillating between prudishness and pornography, found embarrassing or far-fetched. The book was received with bemused deference at the time; however, it has recently been reprinted with an account of the controversy and has transformed our understanding of Renaissance art, while his reading was confirmed in an appendix to the book by the Jesuit theologian John O'Malley.
Michelangelo and Leonardo da Vinci were the artists who preoccupied him in his later years; Michelangelo's sculpture of the naked Christ in the church of Santa Maria sopra Minerva in Rome, to which the church added a loincloth, was one of the key works discussed in The Sexuality.
His book Michelangelo's Last Paintings, on the frescoes of the Conversion of St Paul and the Crucifixion of St Peter in the Cappella Paolina, in the Vatican, appeared in 1975. In 2001, he published Leonardo's Incessant Last Supper, a subtle re-examination of the most famous of Renaissance frescoes, in which he pointed to the combining of the forewarning of betrayal and the institution of the Eucharist which followed it.
When I visited him last year – we both knew we might not meet again – he dismissed the matter of his health in the first few minutes, but for an hour and a half we talked of Michelangelo's Doni Tondo, a circular painting of the holy family, in the Uffizi, Florence. We discussed the affectionate embrace of the figures, and the naked youths who people its background. He was writing an extended essay on the painting and thought that he would leave it unfinished, a fragment.
Leo was twice married, first to Dorothy Seiberling and then to Phoebe Lloyd. Both marriages ended in divorce. In his later years, he was much helped by a devoted assistant, Sheila Schwartz. He is survived by his nephews and nieces.
• Zalman Lev ("Leo") Steinberg, art historian, born 9 July 1920; died 13 March 2011