Sebastian grew up in a bohemian milieu with people for whom poetry was what mattered. His mother was Elizabeth Smart, best known as the author of a lyrical prose masterpiece, By Grand Central Station I Sat Down and Wept. His father was the poet George Barker, one of the stars of the neo-Romantic generation that dominated English poetry in the 1940s. Through his parents he had a lifeline to the poets of an era that was soon to become unfashionable, and he was to maintain friendships with John Heath-Stubbs, WS Graham and others for the rest of their lives. They influenced him, but he added to his inheritance something of the harder edge associated with his own generation.
Literary genealogies and cultural traditions were to prove important, reaching back beyond his parents to their sources of inspiration in the Romantic movement. William Blake is a constant presence, palpably so in The Land of Gold, which is surely his finest book. It is Blake the maker of songs who first comes to mind, but there is also a visionary thread, which links Sebastian to a tradition of mystical thought.
Those sources are on display in a trilogy of groundbreaking books: Damnatio Memoriae (2004), The Erotics of God (2005) and a curious chart of world history and European culture called The Matter of Europe (2005). They range from Saint Augustine through Jacob Böhme to Martin Heidegger. There is also a body of philosophical prose.
If it is Blake the poetry calls to mind, it was probably Byron whom the young Sebastian resembled. He was magnetically handsome and tended to live dangerously. In the poem Curriculum Vitae he refers to a breakdown, and a powerful sonnet sequence called On the Rocks (1977) logs the collapse of his first marriage in all its daily anguish. He had three marriages; the third - to the poet Hilary Davies - transformed everything for him. It was partly as a result of their connection that, in 1997, he was received into the Roman Catholic church. From his first two marriages he had three daughters and a son, to all of whom he was devoted.