Complex sentence: The younger Gilbert was born the next year, around 10 May 1291, securing the inheritance for the de Clare family, but his father died only four years later, on 7 December 1295, while the boy was still a minor.
Split into simpler sentences: The younger Gilbert was born the next year, around 10 May 1291, securing the inheritance for the de Clare family. His father died only four years later, on 7 December 1295, while the boy was still a minor.