Complex sentence: He was the eldest son of marshal Boniface de Castellane and married Pauline de Talleyrand-Périgord, bringing the château de Rochecotte into the Castellane family.
Split into simpler sentences: He was the eldest son of marshal Boniface de Castellane. He married Pauline de Talleyrand-Périgord, bringing the château de Rochecotte into the Castellane family.