During the Soviet era, rock music became extremely popular, because it, as well as folk songs, offered a chance to rebel against the local authorities. Imants Kalniņš was the most important composer of the time, and his songs were extremely popular. He also wrote music for the movie originally called Četri balti krekli ('Four White Shirts'), later given the title Elpojiet Dziļi! ('Breathe Deep!'), which spoke about the need of freedom and was therefore banned. One of the most important social gatherings of the time was the annual Imantdiena ('The Day of Imants (Kalnins)'), forbidden on grounds of interfering with hay-gathering. The tradition continued informally at the composer's house.