In May 1716, the Emperor assured the Electress and the Grand Duke that there was no insurmountable obstacle preventing her accession, but that Austria and Tuscany must soon reach an agreement regarding which royal house which was to succeed the Medici. As an incentive to accelerate Cosimo's reply, the Emperor hinted that Tuscany would reap territorial advancements. In June 1717 Cosimo declared his wish that the House of Este should succeed. Charles VI's promises never materialised. In 1718 he repudiated Cosimo's decision, declaring a union between Tuscany and Modena (the Este lands) unacceptable. On 4 April 1718 England, France and the Dutch Republic (and later Austria) selected Don Carlos of Spain, the eldest child of Elisabeth Farnese and Philip V of Spain, as the Tuscan heir. By 1722 the Electress was not even acknowledged as heiress, and Cosimo was reduced to spectator at the conferences for Tuscany's future.