How did secular rulers challenged papacy authority in the 14th and 15th century?

Secular rulers challenged papacy authority in the 14th and 15th century through an anti-papal campaign (Unam sanctam, a book written by Pope Boniface VIII and issued on 18 november 1302. Some historians considered this book as one of the most extreme statements of Papal spiritual supremacy ever made) and by installing a General Council to regulate the Pope's actions.