Complex sentence: He is said to have divided Ireland into twenty-five shares, one for each of his children, which stood for three hundred years, until the establishment of the provinces under Eochu Feidlech.
Split into simpler sentences: He is said to have divided Ireland into twenty-five shares, one for each of his children. This partitioning of the island stood for three hundred years, until the establishment of the provinces under Eochu Feidlech.