European higher education took place for hundreds of years in Christian cathedral schools or monastic schools (scholae monasticae), in which monks and nuns taught classes; evidence of these immediate forerunners of the later university at many places dates back to the 6th century. The earliest universities were developed under the aegis of the Latin Church by papal bull as studia generalia and perhaps from cathedral schools. It is possible, however, that the development of cathedral schools into universities was quite rare, with the University of Paris being an exception. Later they were also founded by Kings (University of Naples Federico II, Charles University in Prague, Jagiellonian University in Kraków) or municipal administrations (University of Cologne, University of Erfurt). In the early medieval period, most new universities were founded from pre-existing schools, usually when these schools were deemed to have become primarily sites of higher education. Many historians state that universities and cathedral schools were a continuation of the interest in learning promoted by monasteries.