Complex sentence: Charles Ferdinand was left an orphan at an early age, after some schooling at the Lycée Bonaparte in Paris, he attempted vainly to enter the École spéciale militaire de Saint-Cyr.
Split into simpler sentences: Charles Ferdinand was left an orphan at an early age. After some schooling at the Lycée Bonaparte in Paris, he attempted in vain to enter the École spéciale militaire de Saint-Cyr.