In his infancy, John was created Earl of Richmond. With that title, John was admitted into the Most Noble Order of the Garter upon the death of Thomas Holland, Earl of Kent—one of the original knights of the Order.
As a young man, John was described as tall and well-built and was a well-known womanizer. In his young adulthood, John had an affair with Marie de St. Hilaire of Hainaut, a lady-in-waiting to his mother Queen Philippa. From this relationship, an illegitimate daughter, Blanche, was born in 1359.
On 19 May 1359 at Reading Abbey, John married his third cousin, Blanche of Lancaster, the younger of two daughters of Henry of Grosmont, 1st Duke of Lancaster, and his wife Isabel de Beaumont. The wealth Blanche brought to their marriage was the foundation of John’s fortune. He was granted, jure uxoris, the Earldoms of Derby and Lincoln.
In 1361, upon the death of his father-in-law, the 1st Duke of Lancaster, in 1361, John received half his lands and distinction of being the largest landowner in northern England. John inherited the rest of the Lancaster property and the title of Earl of Leicester, when Blanche’s sister Maud, Countess of Leicester, died without issue on 10 April 1362. John received the title Duke of Lancaster from his father on 13 November 1362. In addition, John also became the 14th Baron of Halton and 11th Lord of Bowland and held the high office of Steward of England.
John and Blanche of Lancaster were the parents of Philippa (born 31 March 1360), who became Queen of Portugal when she married John I of Portugal in 1387; John (born 1362), who died in infancy; Elizabeth (born 21 February 1364), who married three times; Edward (born 1365) and John (born 1366), who both died in infancy; Henry Bolingbroke (born 3 April 1367), who later became Henry IV by overthrowing his cousin Richard II; and Isabel (born 1368), who died in infancy.
On 12 September 1368, at the age of 23, Blanche of Lancaster died from the bubonic plague at Tutbury Castle in Staffordshire; at the time, John was in France, serving as a commander in the Hundred Years’ War. Blanche was buried at the old St. Paul’s Cathedral in London. After his wife’s death, John campaigned with his elder brother Edward of Woodstock, participating in many of the battles of the Hundred Years War and aiding ally Pedro of Castile.
Resentment of John’s power and influence, along with the fact that English forces had experienced serious setbacks in the Hundred Years’ War and his father Edward III’s unpopularity due to high taxation and an extramarital affair, resulted in John being partially blamed for the failing government of the 1370s.
On 21 September 1371, John married Constanza, daughter of Pedro of Castile and Léon. Together, John and Constanza had two children, a daughter, Catherine (born 1372) and John (born 1374), who died in infancy.
In January 1372, John claimed the titles of King of Galicia, King of Castile, and King of León by virtue of his marriage to Constanza; however, he was not recognized as such, except for a brief period (1386-1387) when he capture Galicia. In 1388, John and Constanza agreed to renounce all claims to the Castilian throne. In return, their daughter, Catherine of Lancaster, was betrothed to the son King John I of Castile. That son would later become Henry III of Castile, and Catherine would be made queen, thereby uniting the two rival claims.
Even though he was married to Constanza, John’s philandering continued. During this time, John fathered four children by his mistress, Katherine, a widow of Hugh Swynford; her sister Philippa de Roet was married to Geoffrey Chaucer. Those children were John (born 1373), Henry (born 1375), Thomas (born 1377), and Joan (born 1379).
In 1377, Edward III died of a stroke; his successor was his 10-year-old grandson Richard II. During the young king’s youth, John ruled in his nephew’s stead. In 1381, an unpopular poll tax culminated in the Peasants’ Revolt in 1381. At the time of the revolt, John was away from London, thereby avoiding the wrath of the mob. However, one of John’s more opulent residences, the Savoy Palace, situated between the Strand and the River Thames, was destroyed during the rebellion.
In January 1390, John was granted the title Duke of Aquitaine by his nephew, Richard II, who himself had inherited it from his father Edward.
On 24 March 1394, Constanza of Castile died at Leicester Castle and was buried at Newark Abbey, Leicester.
In 1396, two years after she died, John married his longtime love, Katherine Swynford(my two-times 19th great-grandmother). In 1397, their children were legitimized by both Richard II and the Roman Catholic Church and were given the surname Beaufort; however, these children were barred from inheriting the throne.
On 3 February 1399, John died of natural causes at Leicester Castle. He was buried beside his first wife, Blanche of Lancaster, in St Paul’s Cathedral. The two alabaster effigies were notable for having their right hands joined. Sadly, in 1666, their effigies were destroyed, along with the cathedral, in the Great Fire of London.