The development and expansion of the city's favelas can be seen in various stages, influenced by significant events, laws and national and international trends.

The proclamation of the Republic and the abolition of slavery were two extremely significant factors, causing the first major social fracture between freed slaves and disadvantaged groups on one hand, and the aristocracy who benefitted from cheap labor on the other.

Neither the ex-slavemasters nor the ex-slaves were prepared for this profound changes - suddenly, the latter were launched into an unregulated labor market and left their slave quarters for the hills.

The rural economic crisis caused by a lack of slave labor led to high levels of migration from agricultural regions to the then capital - Immigrants from all over the country, and even from Europe, flocked to Rio during this early stage of industrialization, encouraged by false rumors about urban labor supply.