The librettist Alice Goodman has tweeted:
Please pray for the repose of the soul of my husband, Geoffrey Hill, who died yesterday evening, suddenly, and without pain or dread.
Sir Geoffrey, 84, came to attention with the epic Mercian Hymns (1971). Much of his work centres on historic events and the abuse of power, generally rooted in English conditions.
He was professor of poetry at Oxford, 2010-15.
The Reverend Alice Goodman co-wrote Nixon in China and Death of Klinghoffer with John Adams and Peter Sellars.