Complex sentence: He entered the army at an early age, but in 1799 he took part in the republican movement at Naples inspired by the French Revolution; he fought against the Bourbon troops under Cardinal Ruffo, was captured and exiled to France.
Split into simpler sentences: He entered the army at an early age, but in 1799 he took part in the Neapolitan Republic, inspired by the French Revolution. He fought against the Bourbon troops under Cardinal Ruffo, was captured and exiled to France.