then on 15 September to Vörden where the unit stayed until January 1940. There, the Gruppe flew fighter protection during the "Phoney War" on the German border to the Netherlands. Adolph claimed his first aerial victory in World War II on 1 October 1939 over Osnabrück. His opponent was a Royal Air Force (RAF) Bristol Blenheim N6281 of No. 139 Squadron flown by F/O AC MacLachlan. In mid-January 1940, I. Gruppe was ordered to an airfield at Gymnich, today part of Erftstadt, where the unit was tasked with patrolling Germany's western border. There, the Gruppe continuously conducted various flight exercises. In late April, the unit received the first Bf 109 E-4 variant, replacing the Bf 109 E-3s. Battle of France and Britain The Wehrmacht launched the invasion of France and the Low Countries on 10 May 1940. During this campaign, I. Gruppe of JG 1 was subordinated to the Stab (headquarters unit) of Jagdgeschwader 27 (JG 27–27th Fighter Wing) which was under the control of VIII. Fliegerkorps (8th Air Corps) under the command of Generaloberst Wolfram Freiherr von Richthofen. That day, I. Gruppe flew combat air patrols in the area of Venlo–Tirlemont–Liège and later that day to Maastricht. On 12 May, German forces began crossing the bridges over Meuse and Albert Canal. At first light, nine Bristol Blenheims belonging to No. 139 Squadron RAF took off from Plivot to bomb the bridgeheads. They ran into Bf 109s from Stab./JG 51, and 2. and 3./JG 27. In defense of these bridges, I. Gruppe claimed ten bombers shot down, including three Blenheim bombers from No. 139 Squadron by Adolph. No. 139 Squadron lost seven of the unescorted bombers. On 16 May, I. Gruppe was moved to an airfield at Charleville. On 6 June, Adolph was credited with two aerial victories over French Lioré et Olivier LeO 451 bombers in the vicinity of Montdidier, his fifth and last during the French campaign. I. Gruppe moved to an airfield at Plumetot on 30 June 1940 for combat against the RAF. On 5 July, the Luftwaffe began reorganizing its fighter units. In consequence, I. Gruppe of JG 1 was officially integrated into JG 27 as its III. Gruppe, with 2. Staffel of JG 1 then becoming the 8. Staffel of JG 27. On 19 July, III. Gruppe escorted a number of Junkers Ju 87 dive bombers on a Kanalkampf mission to the Isle of Wight