Year 542 (DXLII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. From this year forward, the appointment of particular Roman consuls was abandoned and the office was merged with that of Byzantine emperor. Thus, the consular year dating was abandoned in practice, even though it formally remained until the end of the 9th century. The denomination 542 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.