Complex sentence: Patrick de Lacy Sr. was part of the de Lacy-Billingari family; the suffix "-Billingari" refers to the branch of the de Lacy family from Ballingarry, Limerick, also known as "of La Garthe".
Split into simpler sentences: Patrick de Lacy Sr. was part of the de Lacy-Billingari family. The suffix "-Billingari" was added to some in this branch of the de Lacy family from Ballingarry, Limerick that became known as "of La Garthe".