Whereas the main phonological changes between OJ and NJ took place during the EMJ period, it was during the LMJ period that most of the significant grammatical changes took place which transformed Japanese from its premodern to its contemporary shape in both morphology and syntax. The course and precise dating of some changes is difficult to trace through the written sources; they are mainly observable in the sources dating from the end of the period. It may be no coincidence that sweeping changes took place during a period of civil war and great social upheaval and change which also would have resulted in a relaxation of social and linguistic norms.