International organizations range from the un to voluntary organizations with members in a handful of states. The yearbook of international organizations 2005-2006 lists around 40,000 bodies, of varying shapes and sizes and this does not include multinational corporations. It could be said that they operate in a sphere which transcends the state system in one way or another. But this does not mean that states are irrelevant to their activities far from it. There are examples of international organizations from ancient china through the medieval period. The roman catholic church, which exercised considerable power over pro-modern. Europe, can be regarded as an international organization. However, until the modern period, the scope of such organizations was limited by technology. In the modern era, a notable international organization was the movement against slavery. A world anti-slavery convention was held in london in 1840.