Following the occupation of Switzerland by French revolutionary forces in 1798, a project to raise six demi-brigades of Swiss infantry for French service was initiated. However, recruitment proved difficult and by May 1799 only a quarter of the intended establishment of 18,000 had been raised. Napoleon authorized the recruitment of a Swiss infantry regiment for French service in July 1805. A further three infantry regiments were created in October 1807, each including an artillery company. He specified that this newly raised Swiss Corps should comprise only citizens of Switzerland without "mingling in deserters or other foreigners". The Swiss regiments fought well both in Spain (where they clashed at the Battle of Bailén with Swiss troops in the Spanish Army) and in Russia. During the retreat from Moscow Swiss losses amounted to 80% of their original numbers. The Swiss were allowed to keep the distinctive red coats which had distinguished them prior to 1792, with different facings identifying each regiment.