Why was the Battle of the Volturno Giuseppe Garibaldi’s largest battle?

The Battle of the Volturno (October 1–2, 1860) is recognized as the largest battle of Giuseppe Garibaldi’s career because it involved the largest force he commanded during his military campaigns. By the time he reached the Volturno River north of Naples, he had 30,000 men under his command to face the regrouped forces of King Francis II of the Bourbon Kingdom of the Two Sicilies.1

This engagement served as the final major effort by the Neapolitan army to resist Garibaldi’s advance following his successful Expedition of the Thousand. Although Garibaldi emerged victorious, the battle effectively checked his further progress toward Rome, as political pressures and the intervention of Piedmontese troops soon led to the annexation of the south into a unified Italy under Victor Emmanuel II.21