An electronic organ is a musical instrument with keyboard descended from earlier instruments such as the Harmonium (with bellows or fan), the pipe organ and the theatre organ. This instrument was originally designed to imitate the pipe organ, the theatre organ, the sounds of the big bands and of orchestras. In time, the electronic organ developed in three distinct trends: on one hand, Hammond style organs most used for popular music, on the other hand, the electronic organs for home use such as the combo organs, home organs or the digital organs. The third trend was instead that of the digital church organs, which imitate the classical pipe organ sounds, and were mostly used during religious ceremonies and in churches.