Complex sentence: About 1802/3 Cochrane's actions alienated the Spanish Governor of Ferrol, and then incited an attack on Spanish treasure ships returning from South America, the effect of which was to bring Spain back into the war on France side in 1804.
Split into simpler sentences: About 1802/3 Cochrane alienated the Spanish Governor of Ferrol when Cochrane incited an attack on Spanish treasure ships returning from South America,. The effect of Cochrane's actions was to bring Spain back into the war on France side in 1804.