There is no reference to an annual "field of March" (campus Martius) from the Merovingian period (481–751).
For example, King Childebert II (575–596) promulgated edicts at three assemblies on March 1 in the last decade of his reign.
[4] There is no evidence in Merovingian sources, however, that campaigns were more likely to begin in March or early spring than any other time of the year.
[1] The Marchfield was also a place for royal patronage, the meting out of rewards and punishments and maintaining a direct link between the king and the soldiery.
[5] The assembly could also act as a tribunal, trying persons accused of high treason.