When Charles's son Philip inherited the duchy, Francis invaded Italy. Philippe de Chabot, a French general, led his army into Piedmont in March 1536, and proceeded to capture Turin the following month, but he failed to seize Milan. In response, Charles invaded Provence, a region of France, advancing to Aix-en-Provence, and took Aix in August 1536 but his movement was halted by the French Army blocking routes to Marseilles. Afterwards, Charles withdrew to Spain rather than attacking the heavily fortified Avignon. There is also a story that French troops deliberately left over-ripe fruit on the trees in an attempt to give Charles's troops dysentery. While Charles V was busy fighting for territory in France, he lost focus on events taking place in Italy. Francis I's armies received massive reinforcements in Piedmont in terms of generals, troops, and horses on a march headed for Genoa. France had secured an alliance with the Ottoman Empire in 1536 through the diplomatic efforts of Jean de La Forêt, France's ambassador to the Ottoman Empire. A Franco-Turkish fleet was stationed in Marseille by the end of 1536, threatening Genoa, by planning to attack simultaneously with the French troops marching on land towards the city. Unfortunately for the French and Ottomans, when they arrived in Genoa in August 1536 the defenses of the city had been recently reinforced. Instead, the troops marched onto Piedmont, capturing many towns there. In 1537 Barbarossa raided the Italian coast and laid a siege at Corfu, although this provided only limited assistance to the French. With Charles V unsuccessful in battle and squeezed between the French invasion and the Ottomans, Francis I and Charles V ultimately made peace with the Truce of Nice on 18 June 1538.
Question: How many years after Charles invaded Provence and took Aix did Francis I and Charles V make peace with the Truce of Nice?
Answer: 2