John’s marriage to Blanche of Lancaster gave him wealth and land – including thirty castles across England.  He held Kenilworth, Pontefract, Lincoln, Leicester, Tutbury and Monmouth to name but a few.  Blanche died on 12 September 1368 at Tutbury.

Three years later on 21st September 1371 John married Constanza or Constance of Castile.  The following year at the beginning of February she made a state entry to London.  The marriage gave John a claim to the kingdom of Castile by right of his new wife.  Constance was the daughter of King Pedro – or Pedro the Cruel –   John had had himself proclaimed King of Castile on January 29th.  The state entry reinforced John’s new status and the reason behind it.

Pedro had been usurped by his half-brother Henry of Trastamara and having fled across the Pyrenees sought the help of Gaunt’s elder brother the Black Prince. There were many more twists in the plot but ultimately Henry murdered his brother and claimed the kingdom of Castile ignoring the rights of Constance who was safely in english held territory along with her younger sister Isabella.  It was the Black Prince who escorted Constance into London in February 1372.  The marriage was a dynastic one – shortly after the second marriage Gaunt began his affair with Katherine Swynford.

In the meantime Constance bore two children.  John was born in 1374 but died the following year.  Catherine or Catalina of Lancaster was born in early 1373 or possibly late 1372. Her marriage, like her half sister Philippa’s,  reflected John’s Iberian political aspirations but one of her descendants would be at the centre of a scandal that shook England’s religious foundations.

It was only in 1386 that John was able to raise the funds to mount an invasion of Castile in aid to claim his throne after the King of Portugal defeated the Castilians.  The money came from a loan granted by Richard II on the understanding that it would be repaid once John had his throne.  Richard was leased to see the back of his dominant uncle whilst the nobility – or extended family as you’ve probably now come to think of them- resented his power.  There was an underlying fear that he might seek the throne of England for himself.

Catherine of Aragon, c. 1496, portrait by Juan de Flandes. Fine Art Images/Heritage Images/Getty Images

The Iberian Campaign was not a rip roaring success.  John couldn’t get his Castilian allies to give battle and it wasn’t long before disease began to decimate his army. The Treaty of Bayonne saw John give up his claim to the Castilian throne. In return he received a sizeable payout and his daughter Catalina was betrothed to Henry of Castile. She married him in 1388 and had several children including John II of Castile in inherited the throne whilst still a child.  Her great grand daughter was Catherine of Aragon…back to the cousin issue again! This picture is in the post because its one of my absolute favourites!

Constanza died in March 1394 at Leicester.  Two years later John of Gaunt married Katherine Swynford.  John was fifty-six.  Katherine was forty-six.  She had no power, wealth or title from which John might benefit but she did already have four children by John.