In nothing was his confidence more justified than in the assiduous care and interest that the regent took in the education of the Archduke Charles and his three sisters, who had been placed in her charge.

In 1515 Charles, on entering his sixteenth year, was declared by Maximilian to be of age; Margaret accordingly handed over to him the reins of government and withdrew for the time into private life.

Her retirement was not, however, to be of long continuance.

On January 23, 1516, King Ferdinand of Aragon died, and Charles, who now became King of Castile and of Aragon, was obliged to leave the Netherlands to take possession of his Spanish dominions.
Before sailing he reinstated his aunt as governess, and appointed a council to assist her.

This post she continued to hold till the day of her death, for Charles was never again able to take up his permanent residence in the Netherlands.