Inês de Castro was born circa 1325 as a noblewoman. She was a descendant of the Castilian Royal Family through an illegitimate line. Her grandmother was an illegitimate daughter of Sancho IV of Castile. She also held ties to the Royal Families of Léon and Portugal.
Inês was a maid of Constance Manuel of Villena in 1340. Constance had recently married the future Peter I of Portugal. Peter quickly fell in love with Inês, and he began to neglect Constance. Inês’ family received important posts around the court, which did not make her any friends in the established court. Initially, Peter’s father Afonso IV of Portugal went along with it, perhaps hoping that Inês and her influence over Peter would soon fade. When Constance conveniently died in 1345, Peter refused to marry anyone other than Inês. His legitimate son by Constance, the future Ferdinand I of Portugal, was very frail and not expected to survive long. Between 1346 and 1354 Inês gave birth to four children, of which three lived to adulthood. Afonso would have none of it. He refused to let Peter marry Inês, and she was even banished from court. It was useless as Peter would soon follow her.
In the end, Afonso took the most drastic measure of all. He ordered to have Inês murdered. At the time Inês was at the Monastery of Santa Clara-a-Velha. She was killed by decapitation in front of at least one of her children on 7 January 1355. She was only 29 years old.
Peter hunted down the killers, finally capturing two of them in 1361. They were publicly executed with their hearts being ripped out. Peter had his final revenge when he declared that he and Inês had secretly married. He had become King in 1357 and declared that Inês be recognised as Queen posthumously.
Though it is not confirmed, it is claimed that Peter had Inês’ body disinterred and forced the court to swear allegiance to her body. Her body had been dressed in royal robes, she was wearing a diadem (though I’m not how they went about this with a decapitated body) and the nobility had to kiss the hem of her garment. [ref] The Popular Encyclopaedia. Edinburgh: Blackie & Son. 1836. p. 83[/ref]
She was reburied in the Monastery of Alcobaça where she now lies across from Peter, supposedly so they can look at each other when they are resurrected. Both their tombs are truly gorgeous, and I hope to see them in person sometime.