The Hanover Army
Hanover; Lüneburg; Celle; Calenberg etc. There are/were a lot of designations for the troops that came from Hannover. What´s important to know is that since 1665 Georg Wilhelm Duke of Braunschweig and Lüneburg ruled the Duchy of Lüneburg from Celle. His younger brother Ernst August Duke of Braunschweig and Lüneburg, who was also prince-bishop of Osnabrück, ruled the Duchy of Calenberg from Hannover since 1679. (There were also Dukes of Braunschweig and Lüneburg who ruled the Duchy of Wolffenbüttel, but these are not of interest for this story about the Hanover Army.) For a complete description look at the page about English Royalty
Ernst August and Georg Wilhelm plan to unite Hannover and Celle
All the complications about what's what originate in that from 1682 Ernst August (Hannover) and Georg Wilhelm (Celle) were bent on uniting there territories through their children. George Ludwig of Hannover married Sophie Dorothea of Celle in 1682. In 1683 Ernst August ordered that from then on the first son should inherit everything (primogenitur). In 1692 he became the ninth elector of the empire. In 1698 his son Georg Ludwig inherited Hannover and became elector. He also inherited Celle on the death of his uncle on 28 August 1705. In 1714 he became King of the United kingdom. Later he also succeeded in annexing the Duchy of Bremen and Verden.
Hanover and Celle Armies
After this it should be clear that from at least 1682 the dukes of Hannover and Celle treated almost as one with foreign countries. They also had a rather common policy in more or less permanently renting out troops. These fought against the Turks in Hungary and against France in the Low Countries. Hanover was alone in sending troops to aid the Venetians. Hannover was perhaps a bit stronger than Celle, but both countries had about 10 infantry battalions. When the armies were fused in 1705 the army of Celle counted 14 squadrons and 10 battalions, that of Hannover 18 squadrons and 10 battalions.
Campaigns of the Hanoverian army
At the start of the War of the Spanish Succession the Hanoverian army was very experienced and altogether comparable to that of Bavaria or Prussia. Its first acts in this war was renting out a force of about 5 battalions to the United Provinces, and a sligthly larger to England.