But the war with France was now in full course, and Cavalry was necessary, so the Commander-in-Chief gave orders that the Thirteenth be augmented to a strength of 641 men with the same number of horses. As practically nothing remained of the old Regiment but a few officers, this meant raising a new one. Nevertheless, by August 1799, the task had been accomplished, and two years later the strength had reached 902. The short-lived Peace of Amiens in 1802 caused it to be reduced again, after the custom of the times, by about one-half, but the reduction was as short-lived as the peace, and in 1805, when Napoleon had assembled his great army at Boulogne for the invasion of England, the Regiment stood at the highest strength it ever reached, 1064 men, and the same number of horses. From this time on until 1810 the Thirteenth was kept at home. It was then no longer an Irish Regiment, but a trace of its old connection remained in the fact that it now had as one of its squadron commanders Colonel Patrick Doherty, who had sailed with it for the West Indies in 1796, and that two of his sons were serving in his squadron. So far the war record of the Thirteenth can hardly be said to have been fortunate. In the ninety-five years of their existence they had served with no special distinction in the two Jacobite rebellions, and in one campaign abroad, where their chief enemies had been climate and disease. But this long period of inglorious and yet trying service was now over. In the next five years, before their first century came to an end, they were to cross swords again and again with the finest soldiers in the world, to learn the lessons of war under the greatest of English commanders, and to win for themselves imperishable renown. In February 1810 the Regiment was ordered to prepare 8 troops for immediate service abroad, and before the end of the month they were on board ship. They left behind 2 troops in depot at Chichester, and parted with their Commanding Officer, Colonel Bolton, who had done much to raise and shape the new Regiment after the West Indian campaign. He had just been promoted, and was succeeded by Colonel Head from the Twelfth Dragoons. The 8 troops for active service each numbered 85 men and 85 horses, or 680 men with officers. Before the end of March they had disembarked at Lisbon.