It can be argued variously when the first MNCs emerged in OTL - though the concepts of 'states and nations' had to emerge first for such terms to have any meaning, and that some aspects emerged long before the traditional start of the modern state system, with the Treaty of Westphalia.
Religious bodies and the Hanseatic League displayed some aspects now associated with MNCs, but it can be argued that the persisting Trading Companies are the first MNCs as we would recognise them. The Industrial Revolution, with requirements for goods and markets that crossed national boundaries led to the development of the modern arrangement (though it should be remembered that the vast majority of companies were effectively Mono-National Companies, even if they exported). At the present the largest MNCs have a turnover greater than the GNP of many countries. Many are able to negotiate on their own behalf with administrative figures in various states, to get the most favourable conditions.
In Rise of the Statelets some MNCs have developed somewhat further, and negotiate in international organisations in their own right The presence of many more small states than in OTL means that the companies have an advantage over them - and have been known to encourage or enforce links that are not necessarily approved of by the relevant governments.