Complex sentence: The commercial treaty between France and Britain merely lasted five and a half years--the French harvest failed in 1788-89 and following the outbreak of revolution, the "Ancien Régime" collapsed and with it the Eden Treaty.
Split into simpler sentences: The commercial treaty between France and Britain merely lasted five and a half years. The French harvest failed in 1788-89 and following the outbreak of the French Revolution, the "Ancien Régime" collapsed and with it the Eden Treaty.