Context: The Rebellion was the career highlight for both leaders; Cumberland resigned from the Army in 1757 and died of a stroke in 1765. Charles was initially treated as a hero on his return to Paris but the Stuarts were once again barred from France by the 1748 Treaty of Aix-la-Chapelle. Henry Stuart's entry into the Catholic Church in June 1747 was seen as tacit acceptance the Jacobites were finished and Charles never forgave him. He continued attempts to reignite the cause, including a secret visit to London in 1750 but habitual heavy drinking made him argumentative and hard to work with. In 1759, he met French Chief Minister de Choiseul to discuss another invasion attempt but Choiseul dismissed him as incapable through drink. When his father James died in 1766, Pope Clement XIII refused to recognise him as Charles III, despite the strong objections of his brother Henry. Charles never visited Britain again and died in Rome in January 1788, a disappointed and embittered man.

Question: How many years was it between the Treaty of Aix-la-Chapelle and Cumberland's resignation from the Army?

Answer:
9