The Constitutional Convention took place in Philadelphia between May and September of 1787, aiming to address the problems of the Articles of Confederation, the first American constitution, which granted independence and sovereignty to the states at the expenses of a weak central government, that lacked the ability to levy taxes, regulate commerce, participate in foreign affairs, among others.
Americans found necessary a stronger Federal government with more specific powers and the Congress called the Constitutional Convention.
Northern states saw slavery as cruel and agianst humanity. Southern states saw slavery as the economic backbone of their economy and felt it was necessary.