Complex sentence: Geoffrey de Mandeville, 2nd Earl of Essex (born "circa" 1130, died 1166) was an English nobleman, the eldest son of Geoffrey de Mandeville, 1st Earl of Essex and Rohese de Vere, Countess of Essex.
Split into simpler sentences: Geoffrey de Mandeville, 2nd Earl of Essex (died 1166) was an English nobleman. He was the son of Geoffrey de Mandeville, 1st Earl of Essex and Rohese de Vere, Countess of Essex.