Complex sentence: These incidents, in which a total of 447 slaves belonging to American nationals were freed by 1842, increased tension between the United States and Great Britain, although they had been cooperating in patrols to suppress the international slave trade.
Split into simpler sentences: These incidents, in which a total of 447 slaves belonging to US nationals were freed by 1842, increased tension between the United States and Great Britain. They had been cooperating in patrols to suppress the international slave trade.