Complex sentence: He secretly married Jeanne de Valois-Saint Remy, a descendent of Henri II via an illegitimate branch; their son Louis-Thomas (1718--1799), who was not legitimated by the king, was later exiled to England.
Split into simpler sentences: He secretly married Jeanne de Valois-Saint Remy, a descendent of Henri II via an illegitimate branch. Their son Louis-Thomas (1718--1799), who was not legitimated by the king, was later exiled to England.