The Battle of Marengo (14 June 1800) inaugurated the political idea that was to continue its development until Napoleon's Moscow campaign. Napoleon planned only to keep the Duchy of Milan for France, setting aside Austria, and was thought to prepare a new campaign in the East. The Peace of Amiens, which cost him control of Egypt, was a temporary truce. He gradually extended his authority in Italy by annexing the Piedmont and by acquiring Genoa, Parma, Tuscany and Naples, and added this Italian territory to his Cisalpine Republic. Then he laid siege to the Roman state and initiated the Concordat of 1801 to control the material claims of the pope. When he recognised his error of raising the authority of the pope from that of a figurehead, Napoleon produced the "Articles Organiques" (1802) with the goal of becoming the legal protector of the papacy, like Charlemagne. To conceal his plans before their actual execution, he aroused French colonial aspirations against Britain and the memory of the 1763 Treaty of Paris, exacerbating British envy of France, whose borders now extended to the Rhine and beyond, to Hanover, Hamburg and Cuxhaven. Napoleon would have ruling elites from a fusion of the new bourgeoisie and the old aristocracy.