He was probably the son of Richard Arches of Eythrope (anciently Eythorpe, "Ethorp", etc.), by his wife Lucy Abberbury (or Adderbury), daughter of Sir Richard I Adderbury (c. 1331 – 1399) of Donnington Castle, Berkshire and Steeple Aston, Oxfordshire, twice MP for Oxfordshire. His family, whose name was Latinised to de Arcubus ("from the arches") had been established in Buckinghamshire since at the latest 1309, and held in that county the manors of Little Kimble, and in the parish of Waddesdon the estates of Eythrope and Cranwell. The estate of Arches within the manor of East Hendred in Berkshire had long been held by a family which was called Arches or D'Arches Their heir was the family of Eyston. John Arches (d. circa 1405) of Arches was elected four-times as MP for Berkshire, in 1384, 1390, 1402 and 1404. A family relationship between the Arches families of Arches and Eythrope, which both bore the same canting arms of Gules, three arches argent, was suggested by Bertha Putnam in her work on Sir William Shareshull, but as was remarked upon by Woodger, her suggestion that Sir Richard Arches (died 1417) was the son of Ralph Arches, son of John Arches (d. circa 1405) of East Hendred was clearly physically impossible.
Between 1394 and 1395 he took part in the first military expedition to Ireland of King Richard II and was knighted soon afterwards. He was elected MP for Buckinghamshire in 1402. He was appointed a Commissioner of Array for Buckinghamshire in 1403 and served as a Justice of the Peace for Oxfordshire from 1410 to 1412. In July 1417 he embarked in King Henry V's army for the conquest of Normandy, serving in the retinue of Thomas Montagu, 4th Earl of Salisbury (1388–1428). He died in Normandy on 5 September 1417, presumably killed in action.
Marriages & progeny
He married twice:
- Firstly, before 1410, to Joan Ardern (born circa 1375), granddaughter and co-heiress of Sir Giles Ardern (died 1376) of Drayton, Oxfordshire[disambiguation needed], Oxfordshire, from whom she inherited the Oxfordshire manors of Horley, Ilbury and Wykeham. These thus became possessions of Sir Richard Arches, who moved his residence to Oxfordshire. She was the widow of William Greville of Horley, Oxfordshire, younger son of the great Gloucestershire wool-merchant William Greville (died 1401), of Chipping Campden, another of whose sons was the husband of Joan's sister Margaret Ardern. By Joan Ardern Richard Arches had the following two children:
- John Arches (born 1410), aged 7 at his father's death, who died as a child shortly after his father, without issue, leaving his sister Joan his sole heiresses.
- Joan Arches (1410–1497), who became a substantial heiress. She was a minor aged 7 at her father's death and in 1420 disposal of her marriage was granted to Thomas Chaucer, (died 1434), son and heir of the poet Geoffrey Chaucer and 14 times MP for Oxfordshire. Chaucer had acquired in 1415 most of the lands of Sir Richard Arches' uncle Sir Richard II Adderbury (died 1416), twice MP for Oxfordshire, which included Donnington Castle and manor, Berkshire. In 1421 at the age of 11 she also became heir to the lands of her half-brother Richard Greville (died 1421), of Ilbury in Deddington, Oxfordshire, MP for Oxfordshire in 1420, her mother's son from her first marriage. Joan was married to Sir John IV Dynham (1406–1458) of Nutwell, Devon. Their son and heir was John Dinham, 1st Baron Dinham (1433–1501), KG; they also had at least five daughters.
- Secondly before May 1417, during the last year of his life, Arches married Joan Frome (c. 1386 – 1434), daughter and co-heiress of John Frome (died 1404) of Buckingham, Buckinghamshire and Woodlands (in Horton), Dorset, councillor to King Henry IV and 6 times MP for Dorset and once for Buckinghamshire. She was the widow of William Filliol (c. 1380 – 1416), MP and after Arches' death she remarried before March 1420 (as his 2nd wife) Sir William Cheyne (died 1442), Chief Justice of the King's Bench. Joan died 1 July 1434. She left a will dated 31 March 1420.
- In Buckinghamshire:
- Little Kimble, held from the honour of Wallingford.
- Eythrope, in the parish of Waddesdon, held from the honour of Wallingford. The Dinhams were later said to have made this estate one of their seats.
- Cranwell, in the parish of Waddesdon, held from the honour of Wallingford.
- Cuddington. Recorded in the 14th century as held by Geoffrey D'Arches. This manor descended to the Dinhams through Sir Richard Arches' daughter Joan.
Arches inherited, or possibly purchased at reduced cost, the following Oxfordshire manors from his childless uncle Sir Richard II Adderbury (died 1416), of Donnington Castle, Berkshire, twice MP for Oxfordshire:
- Steeple Aston
He acquired possession of the following Oxfordshire manors, his first wife's inheritance:
His son and heir John Arches (born 1410) died as a child soon after his father's death, and thus his heir became his daughter Joan Arches, later the wife of Sir John IV Dinham (1406–1458) of Nutwell, Devon. Their son and heir was John Dinham, 1st Baron Dinham (1433–1501), KG. The arms of Arches were later quartered by Lord Dinham and later by his heirs the Bourchier family, Earls of Bath.
- Woodger, L.S., biography of Sir Richard Arches, published in The History of Parliament: House of Commons 1386-1421, ed. J.S. Roskell, L. Clark, C. Rawcliffe, 1993
- GEC Complete Peerage, Vol IV, p. 377 (Baron Dinham)
- Woodger, HoP biog of Sir Richard Arches
- "ADDERBURY (ABBERBURY), Sir Richard I (c.1331-1399), of Donnington, Berks. and Steeple Aston, Oxon. | History of Parliament Online". historyofparliamentonline.org. Retrieved 2014-01-25.
- Lysons, Magna Britannia, 1806, re Waddesden Hundred; Woodger, HoP biog of Sir Richard Arches
- Cassel's Latin Dictionary arcus
- Lysons, Magna Britannia, 1806, re Waddesden Hundred
- Modern spelling, formerly Eythorpe, Ethorp (Lysons, Magna Britannia, 1806) etc.
- Heraldic Visitation of Berkshire, vol.56, p.26, within pedigree of Eyston family 
- Woodger, L.S., Biography of Arches, John (d.c.1405), of Arches in East Hendred, Berks., published in The History of Parliament: the House of Commons 1386–1421, ed. J.S. Roskell, L. Clark, C. Rawcliffe., 1993 
- Arches arms later quartered by Dinham, see e.g. Chope, R.P., The Book of Hartland, Torquay, 1940, p.37; visible in stained glass in Bampton Church, Devon (manor of Bampton held by Bourchiers) and sculpted on the Tudor gatehouse of the Bourchier seat Tawstock Court, Devon. See also Flemish tapestry of Lord Dinham (died 1501) in the Metropolitan Museum of Arts, New York (Cloister Collection)
- Putnam, Bertha H., The Place in Legal History of Sir William Shareshull, Chief Justice of the King's Bench, 1350–1361: A Study of Judicial & Administrative Methods in the Reign of Edward III. Cambridge University Press, Cambridge, 1950, pp.286-7, appendix 1
- GEC Complete Peerage, Vol IV, p.377 (Baron Dinham), note h, quoting Sir Richard's Inquisition post mortem
- "CHAUCER, Thomas (c.1367-1434), of Ewelme, Oxon. | History of Parliament Online". historyofparliamentonline.org. Retrieved 2014-01-25.
- "GREVILLE, Richard (d.1421), of Ilbury in Deddington, Oxon. | History of Parliament Online". historyofparliamentonline.org. Retrieved 2014-01-25.
- GEC Complete Peerage, Vol IV, p.377
- "FROME, John (d.1404), of Buckingham, Bucks. and Woodlands, Dorset. | History of Parliament Online". historyofparliamentonline.org. Retrieved 2014-01-25.
- "FILOLL, William (c.1380-1416), of Woodlands, Dorset. | History of Parliament Online". historyofparliamentonline.org. Retrieved 2014-01-25.
- "Eythorpe", Cranwell & Little Kimble, per GEC Complete Peerage, Vol IV, p.377 (Baron Dinham)
- HoP biog
- Victoria County History, Buckinghamshire, Vol.2, 1908, Parishes: Little Kimble
- Modern spelling, formerly Eythorpe, Ethorp (Lysons, Magna Britannia, 1806, re: Waddesdon) etc.
- Lysons, Magna Britannia, 1806, re: Waddesdon
- Victoria County History, A History of the County of Buckingham: Volume 2, William Page (editor), 1908, pp.267-271: 'The parishes of Stone hundred: Cuddington', A History of the County of Buckingham: Volume 2 (1908), pp. 267-271. 
- GEC Complete Peerage, Vol IV, p.377 (Baron Dinham)
- http://www.middlesex-heraldry.org.uk re:monument of Lady Frances Bourchier (died 1612) in the Earl of Bedford's chapel at Chenies, Bucks