Complex sentence: He was the youngest son but eventual heir of John Chaytor, privateer of Newcastle-upon-Tyne, and married Elizabeth, the sole surviving heir of the ancient House of Clervaux, which descended directly from the House of Plantagenet and Charlemagne.
Split into simpler sentences: He was the youngest son but eventual heir of John Chaytor, privateer of Newcastle-upon-Tyne. Sir Christopher married Elizabeth, the sole surviving heir of the ancient House of Clervaux, which descended directly from the House of Plantagenet and Charlemagne.