Mounted Games were the inspiration of H.R.H. Prince Philip. When the late Col. Sir Mike Ansell was Director of the Horse of The Year Show, Prince Philip asked if he could devise a mounted competition for ordinary children which would be fun and which did not necessarily involve owning an expensive Show pony. In 1957, the Horse of the Year Show, (then held in Harringay Arena), staged the first Mounted Games Championship for the Prince Philip Cup and the competition was an enormous success from the start.

However, Pony Club rules stated that riders must finish competing in the games when they reached the age of 14 years. Mr. Norman Patrick, the then Chairman of the Pony Club Mounted Games Committee, felt that there was a need for an organisation where riders could continue to play the games past this age and so decided to form his own organisation.

The Mounted Games Association of Great Britain was founded by Norman Patrick on 21st January 1984 and was originally based at his home, Bunces Farm, Farnham, Surrey. Col. Sir Mike Ansell, the instigator of mounted games, became the Patron of the newly founded Association. There were seven founder teams in the Association :- Avon, Berkshire, Hampshire, Hertfordshire, Surrey, Sussex and South West Wales. It is from these original seven teams that the Association takes it's theme music "The Magnificent Seven".

As the Association continued to grow and develop, more and more county teams joined the Association and in 1994, the Association became a Company limited by guarantee - The Mounted Games Association (Great Britain) Ltd.

MGA Wales forms a part of MGAGB along with MGA England, MGA Scotland, MGA Northern Ireland.

The Association's growth is not confined to Great Britain however & the object of the association is " To encourage friendship between young people of different nations"