In 1496, Joanna, at the age of sixteen, was betrothed to the eighteen year old Philip of Flanders, in the Low Countries.
Philip's parents were Maximilian I, Holy Roman Emperor and his first wife, Duchess Mary of Burgundy.
The marriage was one of a set of family alliances between the Habsburgs and the Trastámaras designed to strengthen both against growing French power.

Joanna entered a proxy marriage at the Palacio de los Vivero in the city of Valladolid, Castile, where her parents had secretly married in 1469.
In August 1496 Joanna left from the port of Laredo in northern Castile on the Atlantic's Bay of Biscay.
Except for 1506, when she saw her younger sister Catherine,  Dowager Princess of Wales, she would not see her siblings again.

Joanna began her journey to Flanders in the Low Countries, which consisted of parts of the present day Netherlands, Belgium, Luxembourg, France, and Germany, on 22 August 1496.
The formal marriage took place on 20 October 1496 in Lier, north of present-day Brussels.
Between 1498 and 1507, she gave birth to six children, two boys and four girls, all of whom grew up to be either emperors or queens.
In 1496, Joanna, at the age of sixteen, was betrothed to the eighteen year old Philip of Flanders, in the Low Countries. Philip's parents were Maximilian I, Holy Roman Emperor and his first wife, Duchess Mary of Burgundy. The marriage was one of a set of family alliances between the Habsburgs and the Trastámaras designed to strengthen both against growing French power.
Joanna entered a proxy marriage at the Palacio de los Vivero in the city of Valladolid, Castile, where her parents had secretly married in 1469. In August 1496 Joanna left from the port of Laredo in northern Castile on the Atlantic's Bay of Biscay. Except for 1506, when she saw her younger sister Catherine,  Dowager Princess of Wales, she would not see her siblings again.
Joanna began her journey to Flanders in the Low Countries, which consisted of parts of the present day Netherlands, Belgium, Luxembourg, France, and Germany, on 22 August 1496. The formal marriage took place on 20 October 1496 in Lier, north of present-day Brussels. Between 1498 and 1507, she gave birth to six children, two boys and four girls, all of whom grew up to be either emperors or queens.
Joanna of Castile