Complex sentence: Eleanor of Aquitaine p.28 Some chronicles mentioned a fidelity oath of some lords of Aquitaine on the occasion of Eleanor's fourteenth birthday in 1136; this and her known age of 82 at her death make 1122 her likely year of birth.
Split into simpler sentences: Eleanor of Aquitaine p.28 On the other hand, some chronicles mention a fidelity oath of some lords of Aquitaine on the occasion of Eleanor's fourteenth birthday in 1136. This, and her known age of 82 at her death, make 1122 more likely the year of birth.