This family is Welsh in origin, and there are records tracing it far back into the Dark Ages, but these records are questionable. They first appear in reliable records living at Castell-y-Mynach, near Llandaff. The manor is called Bryn-y-gynen, and the current house (above) is the residence of the Bishop of Llandaff.
The first to use the surname "Mathew" was David Mathew of Radyr, who lived in the mid-fifteenth century and was the son of Mathew ab Ieuan (living 1397) and Janet, daughter and heiress of Richard Fleming ap Ieuan Dafydd of Pant-y-Corred (from this generation onward Llandaff was the family's main seat). Mathew ab Ieuan was (probably) the son of Ieuan ap Gruffydd ap Madoc and his wife Cecile, daughter and heiress of Aedan ap Gruffydd ap Cynfrigr. One son was Robert (see below); another was Sir David Mathew (c1400-1484) who is supposed to have saved Edward IV's life at the Battle of Towton in 1461, and as a result was made the king's standard-bearer. His lavish tomb can still be seen in the cathedral at Llandaff - the effigy is six feet seven inches, said to be his actual height. He married Gwennlian, daughter of George Herbert of Llandaff (brother of the ancestor of the Herbert Earls of Pembroke), and had seven sons, most of whom had male-line descendants which became the various branches of the family. The fourth son, Thomas Mathew (1438-1470) married Catherine, daughter and co-heiress of Morgan ap Llywellyn ap Ieuan Gethyn, lord of Radyr; and so the branch from which we are descended was known as "Mathew of Radyr" before they settled in Ireland. We know of eight children: David (c1458, married Alice Bele), William (c1460-1528, married Janet Henry of Llangathen, died 1488?, and his widowed sister-in-law Alice Bele), two sons who died as infants (1462 and 1464), Janet (1468, married Thomas Stradling of St Donats, Glamorgan - the same family which produced our ancestor Gwenllian Stradling, mistress of Anthony Wydeville and great-great-great-great grandmother of Elizabeth Poyntz, below), another son who died in 1468, Morgan (c1470, married ? Howell), and Margaret (c1472).
William and Janet Mathew were married about 1485 in Llandaff, and had at least two sons: George (1486) and Henry (1488). By Alice Bele, William also had a daughter, Anne (1490). George married Barbara Bret or Brent (born c1503, of Cossington, Somerset) and he died on November 10, 1557 at Radyr. They had eleven children: Arnold (c1527); Jane (c1529); William (1530); Henry (1533); George (1535); Thomas (1539); Edmund (see below); Catherine (1545); Florence (1549); Janet (1551); and Cecile (1553).
Edmund Mathew was born at Radyr in 1543 and died at Thurles Castle in Ireland, possibly in 1606, though some sources say 1660 - unlikely. He was a physician, a Sheriff of Glamorganshire, and custodian of the sacred relics of St Teilo at Llandaff. He married Jane Skerne (of Long Ashton, Somerset; daughter of Bartholomew, born 1561, Radyr). His son is thought to be the one who sold the Radyr estate, presumably after his father's death, so it is not clear why Edmund would have died in Thurles. There were perhaps eleven children: Jane (married William Phillips, ? Bierly, and her cousin Edmund Mathew), Captain Anthony (2 children), Edward (married ? Crosby), David (married Agnes Pawley), Barbara (married ? Pilkington and Robert Herbert), Elizabeth, George, Katherine (married Anthony Powell and Daniel Lloyd), William (married Elizabeth Powell), Florence (married Nathaniel Jones), and Frances.
Captain George Mathew (1581-1636) is called "of Thurles" because in 1620 he married Elizabeth Poyntz, the widow of Thomas Butler, Viscount Thurles (by whom she was an ancestor of Queen Elizabeth II), and lived on her estates at Thurles in County Tipperary. They had four children: Toby or Theobald (see below); George Mathew of Reaghill and Thomastown (married Eleanor Butler, daughter of Edmond, Lord Dunboyne; one son, Toby, who married a daughter of Bartholomew Faulkes and had seven children, including Anne, wife of Piers Butler, 3rd Viscount Galmoye); Frances Mathew, a nun; and Elizabeth Mathew, who married Edward Butler of Ballyragget; many descendants. George also had a first wife, a daughter of Sir John Domes; they had two children, William and Toby, both of whom died young.
Toby Mathew of Thurles and Annefield (not to be confused with his contemporary cousin, the famous courtier) married Margaret, daughter of Sir Valentine Browne (or possibly of Sir Thomas Browne of Hospital, a cousin) and with her had two children: George (see below) and Elizabeth (died 1704, married Pierce Butler, 4th Lord Caher. Toby married 2ndly Anne Saull and had three more children: Thomas Mathew of Annefield (died 1714, married Honora Ryan, great-grandparents of the first Mathew Earl of Llandaff), James Mathew, married Elizabeth Bourke, and Mary, died unmarried in 1695. Toby's third wife was Catherine Neville (no children).
Toby Mathew's eldest son, George Mathew of Thurles, married (July 1677) Cecilia, daughter of Francis Arundel of Dyles in County Waterford. Their son George left descendants. George married 2ndly (October 16, 1686) Mary Aldworth, widow of Sir Simon Eaton, Bart., and daughter of Richard Aldworth. Their children: Justyn Mathew (1687-1725, unmarried), a daughter who became a nun, and our ancestor Margaret (died 1725), who married Sir James Cotter in 1725.
Robert Mathew, brother of our ancestor Sir David Mathew, married Maud, daughter of Thomas ap Howell, Lord of Brecknock, and was the ancestor of Toby Mathew, Archbishop of York 1606-1628, father of the famous courtier Toby Mathew (died 1655), a favorite of Queen Henrietta Maria and the man credited with introducing chocolate to England. Yet another cousin, Father Theobald or Toby Mathew (1790-1856) was a leader of the temperance movement in Ireland.