Force of Change: Capital Status
Rome's status as a capital city almost solely sustained Rome’s population and economy throughout its existence.
During the Roman Empire, wealth poured into the city from its conquests. The city produce little food and almost no industry. Without these funds, Rome would not have grown past a small town.
And therefore, when Rome lost its status after Constantine moved the capital to Istanbul, Rome's decline caused the population to fall from 1.6 million to 50,000.
The only factor that kept Rome from collapsing completely was the fact that the Catholic Church made Rome its center and assumed the leadership role through the middle ages. The presence of the church also created a pilgrimage destination which brought visitors to the city, despite the decline. (Karabenick, 1963)
Later, during the Renaissance, the Church was responsible for starting the process of restoring the glory of ancient Rome to reflect the greatness of the Catholic Church.
After ruling the city of Rome (part of what was called the Papal States) for over 1,000 years, the church lost power to a secular force under King Emmanuel in 1871 that unified the new nation of Italy. This brought the governmental capital back to Rome and revived the economy. New offices and people brought flood of building projects, along with the craftsmen and laborers to build them.