The last important act of Margaret, like her first, was connected with the town of Cambray.

In this town, as the representative and plenipotentiary of her nephew the emperor, she met, July, 1529, Louise of Savoy, who had been granted similar powers by her son Francis I, to negotiate a treaty of peace.

The two princesses proved worthy of the trust that had been placed in them, and a general treaty of peace, often spoken of as "the Ladies' Peace," was speedily drawn up and ratified.

The conditions were highly advantageous to the interests of Spain and the Netherlands.

On November 30 of the following year Margaret died, as the result of a slight accident to her foot which the medical science of the day did not know how to treat properly, in the 50th year of her age and the 24th of her regency.
Charles, who had a few months previously reached the zenith of his power by being crowned with the iron crown of Lombardy and with the imperial crown at the hands of Pope Clement VII at Bologna (February 22 and 24, 1530), appointed as governess in Margaret's place his sister Mary, the widowed queen of Louis, King of Hungary, who had been slain by the Turks at the battle of Mohacs, August 29, 1526.
Mary, who had passed her early life in the Netherlands under the care of her aunt Margaret, proved herself in every way her worthy successor.