Twombly’s “literariness” is something that has consistently told against him, along with his fancy foreign ways and his “insinuating elegance”. But his art, as Serota acknowledges in the catalogue, has always been elusive and, for many people, even enthusiasts of contemporary art, unfathomable. Twombly himself has maintained an unusual reticence. In the mid-50s, he wrote a short statement for the Italian art journal L’Esperienza moderna: “To paint involves a certain crisis, or at least a crucial moment of sensation or release; and by crisis it should by no means be limited to a morbid state, but could just as well be one ecstatic impulse…”

A good number of his drawings, paintings and sculptures consist of little other than an inscription. “Twombly writes as if he were seeking out the meaning of the poetic words through the physical act of producing their graphic signs,” Richard Shiff has written. “The word as disembodied sign becomes the word as embodied mark, imbued with the spirit of a gesture and located in a particular place and time.”

Twombly’s has long been an art of indirection; a palimpsest of obfuscations and excisions, of rubbings out and submergings. Like Rauschenberg, who as a young man spent three weeks erasing a drawing he had acquired from Willem de Kooning (the result is a white sheet of paper bearing the faint, ghostly shadow of its former markings), Twombly, in Serota’s words, evokes rather than describes.

Nowhere is his genius for evocation – for suggesting the mood or feeling of a place or a moment – more apparent than in the set of 24 drawings he made in 1959 called Poems to the Sea. “The sea is white three-quarters of the time, just white – early morning,” Twombly told Sylvester. “The Mediterranean at least . . . is always just white, white, white. And then, even when the sun comes up, it becomes a lighter white.”