Borbála, the lover of Matthias
The king stayed in Diósgyőr Castle near Miskolc on 13 November 1473 because it was the day when he signed a document there. In this German letter, he gifted a house in Besztercebánya (Banská Bystrica) and a mine along with agricultural buildings and lands with several villages to a woman called Borbála. Borbála was from Stein which is located on the bank of the Danube in Lower-Austria, today it belongs to Krems an der Donauh.
Yes, she was his lover, the mother of his illegitimate son, János Corvin who was born in 1473 (see the picture).
Matthias wed the Italian Beatrix just three years later and she could never have a child.
Towards the end of Matthias’ reign, the king was desperately trying to give lots of lands and offices to his only son and was thinking of divorcing Beatrix but he died in the very year when Beatrix has heard of that.
Beatrix accused Borbála of witchcraft, telling that she made her barren. Beatrix called János „figliolo della putana”, the son of a whore. Actually, Beatrix’ father had been an illegitimate son, too. Yet, the Queen tried to make the Pope excommunicate Borbála.
When the document was signed in 1473, János was just half year old; we can learn from it that the lovers had met in Vienna but they were together in Diósgyőr. In the picture, you can see the “Thurzó House” on the main square of Besztercebánya which was given to Borbála. Later, Borbála got married and moved to the Castle of Enzersdorf but the king visited her there, too. She left a Last Will in 1491, then she went to the Nunnery of Klosterneuburg. (See its church in the picture.) She died there in 1495 and was buried in the St. Ágnes Chapel.
(Source: Ritoókné Szalay Ágnes and Miskolc Blog)