Basically the ruling class dictated the rules, norms, laws, culture, religion etc. of every epoch of human history. Thus the king and the nobility dictated ‘life’ to all their subjects under monarchies. The traders and emerging factory owners did not like this very much and demanded ‘no taxation without representation.’
This eventually led to the French revolution which saw these middle class traders become the new rulers after overthrowing the nobility. Given that the wealth of traders and manufacturers depended on property and labour the commons was quickly privatised and the European peasants driven into towns where they had nothing to sell other than their labour.
In this way the world became capitalist as the Europeans in need of more raw materials, minerals, labour, markets and land began moving into Africa, the Americas and Asia – colonising almost all of the rest of the world. The people finding themselves in these colonies were likewise press-ganged into factories, mines and towns after being alienated from the land and other means of production. The world became divided between workers and owners. And globally between white and black (including yellow and red here).
Therefore, what we currently have is the dictatorship of the owners, also known as capitalism. The owners determine how and where we live, how and where and when we work and even how, when and where we sleep, find recreation, reproduce etc. This situation is untenable as it gives rise to inequality, exploitation, oppression, discrimination. Hence those who work are constantly in a struggle against those who own.
This struggle finds expression in trade unions, political parties, liberation wars and revolutions. Hopefully humanity will one day obtain a classless society. To get there those who work must seize power from those who own.
However, those who own are not going to give up their wealth and privilege without a fight, so those who work will need to take dictatorial steps to realise the social appropriation of the social product. Hence the dictatorship of the proletariat ( (The proletariat is a fancy word for those who work, it means those who are politically most aware of and understand their exploitation, oppression and the discrimination against them and who are prepared to fight to end it).