The Voluntary Aid Detachment (VAD) referred to a voluntary unit providing field nursing services, mainly in hospitals, in the United Kingdom and various other countries in the British Empire. The most important periods of operation for these units were during World War I and World War II. The VAD system was founded in 1909 with the help of the Red Cross and Order of St. John. By the summer of 1914 there were over 2,500 Voluntary Aid Detachments in Britain. Of the 74,000 VAD members in 1914, two-thirds were women and girls.