Einion Offeiriad
 Einion Offeiriad (“Einion the Priest”) (d. 1356) was a Welsh language poet and grammarian.Einion lived in Ceredigion where he was a chaplain to Sir Rhys ap Gruffudd ap Hywel ap Gruffudd ab Ednyfed Fychan a wealthy nobleman. Amongst Einion’s surviving poems is an awdl sung is praise of Sir Rhys ap Gruffudd.Einion’s fames lies primarily with his metrical grammar ‘llyfr cerddwriaeth’ the earliest of its kind known in Welsh.