I have always wondered why they chose that name for her too!
Anyway, here is the biography of a Portuguese queen whose story I love: Inés de Castro.
Inés de Castro (1327, Vigo, Galicia, España-1355Coimbra, Portugal
Inés was the bastard daughter of a noble from Galicia and she was the half-sister of Juana de Castro, who would be later seduced and illegally married to Pedro I of Castile.
Inés, although illegitimate, had a good education and was sent to Portugal with princess Constanza Manuel de Castilla, who was to become Prince Pedro of Portugal's wife. Inés was one of her ladies-in-waiting and was just 12 years old.
Pedro was at the time in love with a Portuguese courtier. Constanza, very jealous, sent Inés to Pedro because she thought that, as Inés was one of her sweetest maids, she would succeed to convince Pedro of abandoning his mistress. Well, he did abandon her, but only because Inés was prettier.
He soon fell in love with young Inés and he made her his mistress. Constanza, desperate for her husband's love, asked the couple a favour when she gave birth to her first son, Luis. They were to be the godparents of the child and, for some reason, this barred them from ever having carnal contact. But, however, the baby died and Pedro and Inés could become lovers again.
Constanza died in 1345 and two children were left from her marriage: Maria and Fernando. By then Inés, called "Heron's neck", was already Pedro's official mistress and they lived happy together with their children: Beatriz (1347-1381), Alfonso (1348-1356), Juan (1349-1397) and Dionisio (1354-1397).
Alfonso IV, Pedro's father, was fed up with this situation because he wanted his grandson Fernando to be brought up with his father and a convenient wife and not "the Heron Whore", as Alfonso called Inés. On January 7th, 1355, Inés's throat was slit on the orders of Alfonso IV. His son was so angry that a war between father and son started.
When in 1357 Alfonso IV died Pedro became King of Portugal. He declared the he had married Inés de Castro on the 1st January 1354 and that their children were legitimate. Then, he made her corpse be exhumed and seated her on a throne with a Crown put on her head. She was then officially crowned Queen Inés of Portugal, already dead! Strange spectacle for courtiers, watching the coronation of a dead corpse!
Pedro never married again, none of Inés's children became King of Portugal.