Final answer:
Giuseppe Garibaldi was a good military leader who fought for a united Italy but was ultimately unsuccessful.
Step-by-step explanation:
A good military leader who was killed when trying to unite Italy was Giuseppe Garibaldi. Garibaldi was an adventurer, a romantic nationalist, and a revolutionary who spent most of his adult life as a mercenary. He played a key role in the Revolutions of 1848 and fought for a united Italy, but his hopes were dashed by the Austrians, the French, and the papacy. Despite his efforts, Italy was not fully united during his lifetime.