Ola!
During the prelude of the American Revolution, the citizens of the 13 Colonies became disgruntled and dissatisfied with George III’s rule.
His near tyrannical power over the colonists, with his 24/7 strong arming of the British Parliament, was the prime reason of the American Revolution.
The answer is; the Constitutional Convention convened to discuss what the laws of the country should be. They believed that one person should not have absolute power, and it should be delegates among a wide expanse of people and agencies.
You might want to reword this, but this is the general explanation. I hope this helped!
~<3