[3] The institution of contests between the Rio de Janeiro samba school from the 1930s onwards compelled them to commit themselves to presented themes, which began to narrate mainly episodes and exalt characters from the official Brazilian historiography.
It is important to note that the samba-enredo is one of the criteria used by the Judging committee to decide who is the winner of the Carnaval parade competition.
Well in advance of the Carnaval parade, each samba school holds a contest for writing the song.
The samba-enredo is written by these numerous composers mentioned above only after the Carnival Art Director, or "Carnavalesco", officially publishes the samba school's parade theme synopsis for the year.
After a careful explanation of the parade-theme, many times done by the Carnival Art Director himself, composers may ask questions in order to clarify the synopsis, so they can start writing the samba-enredos.