The Lordship of Meath covered a large area of almost 6,000 km2 (c. 1.5 million acres), which became increasingly unmanageable as English power in Ireland receded throughout the 13th century.

Following several informal divisions and squabbles among de Lacy's descendants over control of the lordship, it was finally divided in 1297 and the much smaller, though still sizable, County of Meath was shired.

This situation left part of County Meath within the Pale, while other areas which were once loyal to the Crown were now outside the control of the authorities in Dublin.

Baronies and Cantreds were Norman-era subdivisions of Ireland employed for administrative, justice, taxation, and peerage purposes.

By the 15th century, a beleaguered fort near Mullingar, often burnt by the O'Farrells and located just 80 km (50 miles) from Dublin, was the westernmost outpost that the English controlled in Ireland.

The new baronies created as a result of the act were: Mullingar was named as the "head and shire town" of Westmeath and a Dominican priory in the area was converted into a gaol.

Although there is often (usually satirical)[10][11] discussion within Ireland of Meath and Westmeath re-unifying, proposals to do so have never been seriously considered at either local authority or national level.