Cox's career took off when Lord Ligonier led the Flanders campaigns of the War of the Austrian Succession. In one letter sent back to London, Richard Cox made a demand that "suitable winter provisions and housing should be made available for the three English companies" and he became entwined with logistics and the general welfare of the troops. Ligonier made Cox his private secretary in the late 1740s, went on to become the colonel of the First Foot Guards (Grenadier Guards) in 1757, and rewarded Cox with the post of "military agent" after the incumbent died in May 1758. Thus was born Cox & Co.