11 February 1717 – 11 January 1791), also known as William Williams, Williams Pantycelyn, and Pantycelyn, is generally seen as Wales's premier hymnist.
He is also considered today as one of the great literary figures of Wales as a writer of poetry and prose.
In religion he was among the leaders, with Howell Harris and Daniel Rowland, of the 18th-century Welsh Methodist revival.