The effect of the guns in an operational context was first demonstrated during the actions at Veracruz in 1838, at Campeche in 1843, Eckernförde in 1849 during the Danish–Prussian War, and especially at the Battle of Sinop in 1853 during the Crimean War. The Naval Battle of Campeche made history because it was the first time both sides used explosive shells and the only time sailing ships defeated steamers.