The system for running theatres underwent profound changes from the 1860s. Theatre by the hour, in which the audience could see several works in the same session, meant that more people could attend the shows and was an incentive to composing new works. Zarzuela reduced in size and became satirical in tone, typically one of social criticism and costumbrismo. The genre known as "género chico" emerged at that time, seen as a specific sub genre of zarzuela, associated particularly with the Apolo Theatre, where composers such as Federico Chueca and librettists such as Miguel Ramos Carrión met with great acclaim.