Joan Beaufort was the youngest of the four legitimised children and only daughter of John of Gaunt, 1st Duke of Lancaster, by his mistress, later wife, Katherine de Roet. Joan married Ralph de Neville
Richard Neville, 5th Earl of Salisbury, who displays the arms of Neville (tinctures transposed in error) with a label compony of Beaufort for difference. Salisbury Roll of Arms
Joan Beaufort and mother Katherine Swynford's tomb – 1809 drawing
The tomb of Joan Beaufort and her mother Katherine Swynford the presbytery of Lincoln Cathedral.
Katherine Swynford
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Katherine, Duchess of Lancaster was the third wife of John of Gaunt, Duke of Lancaster, the fourth son of King Edward III. From her earlier marriage, she is known as Katherine Swynford.
Katherine Swynford, from her tomb
Katherine's tomb, the larger tomb, next to the tomb of her daughter, Joan Beaufort. Drawing by William Dugdale.
Geoffrey Chaucer reciting Troylus and Criseyde: early 15th-century manuscript of the work. Currently at Corpus Christi College, Cambridge.