Complex sentence: The Venezuelan crisis of 1902--03 was a naval blockade from December 1902 to February 1903 imposed against Venezuela by Britain, Germany and Italy over President Cipriano Castro's refusal to pay foreign debts and damages suffered by European citizens in the recent Venezuelan civil war.
Split into simpler sentences: The Venezuelan crisis of 1902--03 was a naval blockade imposed against Venezuela by Britain, Germany and Italy and lasted from December 1902 to February 1903. The blockade was a result of President Cipriano Castro's refusal to pay foreign debts and damages suffered by European citizens in the recent Venezuelan civil war.