During World War II, the Lingayen Gulf proved a strategically important theatre of war between American and Japanese forces. On 22 December 1941, the Japanese 14th Army under Lieutenant General Masaharu Homma landed on the Eastern part of the gulf at Agoo, Caba, Santiago and Bauang, where they engaged in a number of relatively minor skirmishes with the defenders, which consisted of a poorly equipped contingent of predominantly Filipino and American troops, and managed to successfully invade and occupy the gulf. Following the defeat, the next day General MacArthur issued the order to retreat from Luzon and withdraw to Bataan. For the next three years, the gulf remained under Japanese occupation prior to the Lingayen Gulf Landings. At 09:30 on 9 January 1945, the U.S. 6th Army conducted an amphibious landing on the gulf, following a devastating naval bombardment, with 68,000 troops landing on the first day alone, and a total of 203,608 in following landings along a 20 mi  beachhead, stretching from Sual, Lingayen, and Dagupan  in the west, and San Fabian  in to the east. Despite the Americans' success in driving out the Japanese army encamped at the Gulf, the Americans suffered relatively heavy losses, particularly on their convoys due to Japanese kamikaze suicide attacks. From 4 through 12 January, a total of 24 ships were sunk and 67 damaged by kamikaze planes, including the battleships USS Mississippi and Colorado , the heavy cruiser USS Louisville , the light cruiser USS Columbia, and the minesweepers USS Long and Hovey. Following the amphibious landings, the Lingayen Gulf was turned into a vast supply depot for the rest of the war to support the American and Filipino assaults on Manila and the rest of Luzon, and thence to Okinawa.
Question: On what date did General MacArthur issue the order to retreat from Luzon?
Answer: 23 December 1941