As a genre of public prayer, litanies have been around for at least 2,500 years. Probably more. In the Hellenistic period, they were standard forms in the mystery religions and in Judaism as well. In the early church, they were always "stational," meaning they were done as part of processions, especially during times of distress (e.g. earthquake, invasion, etc.). A cantor would call out a verse and the people would respond. There were several litanies like this in the East, and, according to tradition, one of the ones used today in the Roman Catholic church dates to about the 6th century or so.