Richard Fitzalan, earl of Arundel and Surrey, was the eldest son of Edmund Fitzalan, earl of Arundel (1 May 1285-17 November 1326) and Alice (c. 1287-before 1338), sister of John de Warenne, earl of Surrey. As Surrey had no children by his wife Jeanne de Bar, Edward II's niece - though he had plenty of illegitimate ones - Richard Fitzalan was his uncle's heir as well as his father's, and was one of the richest men in England. Richard was probably born in 1313 or at the beginning of 1314: according to a papal letter of 1345, he was seven when he married the eight-year-old Isabel Despenser, eldest daughter of Hugh the Younger, at Havering in Essex on 9 February 1321. Edward II attended the wedding and paid for a piece of Lucca cloth to make a veil for spreading over the heads of the child-couple during their nuptial mass, and gave two pounds in pennies to be thrown over them at the chapel door.  Earl Richard was and is known by the nickname 'Copped Hat' (whatever that means). I'm not a great fan of Richard, to put it mildly, but I can't help but admire him for his actions in the summer of 1330, when he was still only a teenager: he rebelled against the regime of Isabella of France and Roger Mortimer, and, named as 'the king's enemy and rebel', was forced to flee the country. Edward III, shortly after he overthrew his mother and her favourite a few months later, recalled Richard to England and restored him to his lands and goods. 
Richard Fitzalan and Isabel Despenser's only child, Edmund Fitzalan ( I use the name Fitzalan in this post, but the family mostly called themselves 'de Arundel' in the fourteenth century), appears to have been born in 1327 - he was said to be twenty in 1347 - when both his parents were still extremely young, probably only fourteen and fifteen. 1327 must have been a bleak year for the young couple: their fathers and Isabel's grandfather the Elder Despenser had recently been executed as traitors, Isabel's mother Eleanor de Clare and eldest brother Hugh (the Even Younger, 1308/09-1349) were in prison, her great-uncle Edward II had been deposed, and three of her four younger sisters had been forcibly veiled by the supposedly merciful Isabella of France. (The youngest, Elizabeth, only a baby in 1327, married Roger Mortimer's grandson Maurice, Lord Berkeley.) Perhaps not surprisingly, Richard and Isabel's marriage was not a happy one, and in December 1344 Richard managed to have it annulled on the grounds that the couple had been "forced by blows to cohabit, so that a son was born" even though they had "expressly renounced" their marital vows at puberty, having been forced in childhood to contract them "by fear of their relatives."  This may be true, though none of the said relatives were still alive to object, and Richard's affair with the widowed Eleanor of Lancaster no doubt had a great deal to do with his desire for an annulment. He married her with unseemly haste in February 1345, in the presence of Edward III.  Eleanor (c. 1318-1372) was the fifth of the six daughters of Henry, earl of Lancaster (d. 1345) and Maud Chaworth (d. c. 1321); sister of the great Henry of Grosmont; and widow of Henry Beaumont's son and heir John, killed jousting in 1342. To add insult to injury, she was also Isabel Despenser's first cousin (Maud Chaworth was the elder half-sister of Hugh Despenser the Younger). Richard Fitzalan and Eleanor of Lancaster were to have five children who survived into adulthood: Richard, born c. 1346, Richard's successor as earl of Arundel and beheaded by Richard II in 1397; John (drowned in 1379), marshal of England; Thomas (d. 1414), archbishop of Canterbury; Joan (d. 1419), countess of Hereford and grandmother of Henry V; Alice (d. 1416), countess of Kent. Isabel Despenser appears not to have re-married, and falls into obscurity after the annulment; she was still alive in 1356 (Note: Douglas Richardson discovered this), but the date of her death is not known. The date of Edmund Fitzalan's death is not known either, but was between 1376 and 1382.
Edmund Fitzalan, although he sent an indignant petition protesting his treatment to the pope in 1347, was made illegitimate by the annulment of his parents' marriage. Despite his illegitimacy, he was knighted and made an excellent marriage, sometime before the summer of 1347, to Sybil, one of the daughters of William Montacute, earl of Salisbury (d. 1344) and Katherine Grandisson. Sybil's siblings included William, earl of Salisbury (1328-1397), Elizabeth, who married Edmund Fitzalan's uncle Hugh, Lord Despenser (died 1349), son and heir of Hugh the Younger, and Philippa, who married Roger Mortimer's namesake grandson and heir, the second earl of March (1328-1360). Edmund Fitzalan and Sybil Montacute had three daughters: Elizabeth, who married Sir Leonard Carew and has descendants; Philippa, who married Sir Richard Sergeaux and has descendants; and Katherine, who married someone called Deincourt. (For more info about Edmund, see Susan Higginbotham's excellent post about him.) I find Richard Fitzalan's willingness to disinherit a male heir puzzling; there was evidently nothing wrong with Edmund, and although Richard was to have three sons by Eleanor of Lancaster and knew before marrying her that she was fertile (she had a son and a daughter by John Beaumont), he couldn't have known for certain beforehand that she would bear him sons, or that they would survive childhood.
Richard Fitzalan, earl of Arundel, wrote his will at Arundel Castle on 5 December 1375, and died on 14 January 1376. He was buried next to Eleanor of Lancaster, who had died in January 1372; their tomb and effigies still exist in Chichester Cathedral (pic here) and inspired Philip Larkin's great poem 'An Arundel Tomb'. Richard, although one of the richest men in England, did not leave a single bequest to his eldest son Edmund or to his granddaughters Elizabeth, Philippa and Katherine. The following were named in the will and left bequests: his and Eleanor's sons Richard, John and Thomas (then bishop of Ely); his daughters Joan and Alice; the eldest daughter (unnamed) of his son John; Henry and Edward, younger sons of his son John; William, another son of his son John; his sister 'Dame Alaine'; his nephews and nieces, Alaine's children by Roger Lestrange; his uncle John Arundel (perhaps an illegitimate son of Richard, earl of Arundel who died in 1302). Richard asked his executors Hugh Segrave, Guy Brian and Edward St John in the last line of his will "to be good to my children," but evidently didn't include his eldest son Edmund in this...
1) Thomas Stapleton, 'A Brief Summary of the Wardrobe Accounts of the tenth, eleventh, and fourteenth years of King Edward the Second', Archaeologia, 26 (1836), p. 338.
2) Calendar of Fine Rolls 1327-1337, p. 181; Calendar of Patent Rolls 1330-1334, p. 20; Calendar of Close Rolls 1330-1333, p. 81.
3) Calendar of Papal Letters 1342-1262, p. 254.
4) Ibid., p. 164.
5) Ibid., pp. 176, 188.