On the 21st October 1496 a decisive marriage took place in the city of Lille, in Burgundy: Joanna of Castille and Aragón, later known as Joanna the Mad, married Philip of Burgundy, later known as Philip the Handsome. This marriage, together with another one between John of Castile of Aragón and Margaret of Austria in 1497, sealed the double alliance between the Catholic Monarchs and the Habsburg dynasty. In 1500 Joanna the Mad and Philip the Handsome had a baby called Charles, who would later become king and emperor: Charles V.
On this link you have some more information about Joanna's trip to Burgundy and the love at first sight Philip and her had the first time they met:
And here you have a short video from the TV series Isabel with some curiosities about Joanna's trip to meet her future husband and the first time they saw each other: