This question is about the emphasized sentence in the following paragraph from Proposed Roads to Freedom by Bertrand Russell:
Socialism as a power in Europe may be said to begin with Marx. It is true that before his time there were Socialist theories, both in England and in France. It is also true that in France, during the revolution of 1848, Socialism for a brief period acquired considerable influence in the State. But the Socialists who preceded Marx tended to indulge in Utopian dreams and failed to found any strong or stable political party. To Marx, in collaboration with Engels, are due both the formulation of a coherent body of Socialist doctrine, sufficiently true or plausible to dominate the minds of vast numbers of men, and the formation of the International Socialist movement, which has continued to grow in all European countries throughout the last fifty years.
This is the first time I have ever seen the structure 'To somebody are due X and Y'. Does the author mean both X and Y are due to (caused by) Marx, where X is 'the formulation of a coherent body of Socialist doctrine' and Y is 'the formation of the International Socialist movement'?