Orthodox Church organization is based (theoretically) on the principle of the autonomous or autocephalous local churches. The smallest instance of The Church is a local eucharistic community, which contains and expresses the catholicity of the whole church. These local communities are governed by bishops who constitute the ruling body of the Church. In theory each geographic area should have only one bishop, but the practise nowadays seems to be that each nationality has its own hierarch. This goes againts the traditional Orthodox ecclessiology.