St John Ambulance, branded as St John in some territories, is a common name used by a number of affiliated organisations in different countries dedicated to the teaching and practice of medical first aid and the provision of ambulance services, all of which derive their origins from the St John Ambulance Association founded in 1877 in the United Kingdom. Each national group falls within the charge of a Priory or National Council of the Venerable Order of Saint John in which each Priory ranks alongside the others. In several priories St John Ambulance has commercial sections or subsidiaries operating to generate surplus for charitable activities; these are structured much like other commercial bodies. The membership aspect of St John Ambulance is largely ranked, and members fall into a hierarchical structure of command. Ranks run from corporals, through sergeants and officers all the way up to high national ranks, but there is significant variation between Priories and it is hard to generalise the structure too much from an international perspective. Most members of St John Ambulance are not themselves members of the Order, and vice versa, so a major presence of the Order does not dictate a major presence of St John Ambulance. Most notably, the Order of St John is a Christian organisation, whereas St John Ambulance is keen to ensure there is no allegiance to any particular religion or denomination, so as to remain available to all. St John Ambulance works on a more geographical nature than the Order, and has to contend with the differing national laws, medical practices and cultures of countries.