Polish to English Social Sciences Religion Religious/folk tradition

The text is discussing the activities of a theatre company:

"The times the company chose for their journeys were linked with the ritual year in the countryside; around Easter they travelled with ‘Alilujki’ , around Christmas with carols, performing these rituals, worked on anew, in villages where they were still remembered but had now been lost"

The word itself doesn't necessarily have to be translated. A brief explanation/definition would be fine - but I haven't managed to find one yet and the deadline looms.....

All help most gratefully received :-)