commonship

A state, condition, or things shared or held in common; commonality.

The two languages develope in different directions but the old commonship is still discernible.

A community or fellowship.

If they do not agree, then, as already mentioned, it is reserved to His Majesty, together with the approving Assembly, to effect the proposed change in the portion of the Monarchy concerned, to dissolve the commonship, and to make the consequent administrative arrangements; […]

There was even a commonship between the mine operators and the men at one time, before the Great Depression.