The oath of supremacy was simply a lever for evicting the owners of the land.

The process was simple.

The king demanded spiritual allegiance; refusal was high treason; the punishment of high treason was forfeiture of estates, with death or banishment to the recusants.

Any other law they might have obeyed, and retained their inheritance.

This law fixed its iron grapples in the conscience, and made obedience impossible, without a degree of baseness that rendered life intolerable.
Hence Protestantism was detested, not so much as a religion, as an instrument of spoliation.
The agrarian wars were kept up from generation to generation, Ireland always making desperate efforts to get back her inheritance, but always crushed to the earth, a victim of famine and the sword, by the power of England.
The history of these wars, then, is the history of the case of the Irish patient.