Louise Élisabeth was bored when she returned to Parma, and sought a wider realm to rule. She allied herself with Empress Maria Theresa, who promised Louise Élisabeth the throne of the Southern Netherlands, which had been returned to Austrian rule under the Treaty of Aix-la-Chapelle. This alliance was to be cemented by the marriage of her daughter Princess Isabella to Archduke Joseph of Austria. The marriage took place in 1760.