The calendar used in the Republic of the Serenissima, until 1797, corresponded to the oldest Roman calendar where March was the first month of the year - replaced only later by January - and with it its first day marked the New Year.
More veneto means "according to the Venetian custom / in the Venetian way", which was abbreviated as m.v. next to the date used in the documents and annotations, to indicate their different use according to the most common style at the time. Since, beginning in March, the beginning of the year was postponed by two months, the difference in dating was substantial and "late" by one year. As an example, on February 13, 1598 m.v. corresponded to February 13, 1599 of the Gregorian calendar.
There is talk of an ancient calendar precisely because it has its roots in the birth of Rome where, according to tradition, Romulus - the first king - established the city and the first calendar. In it the months were 10: Martius, Aprilis, Maius, Iunius, Quintilis (later Iulius in honor of Julius Caesar), Sextilis (later Augustus in honor of Cesare Ottaviano Augusto), September, October, November, December. Only with Numa Pompilio - second king of Rome - the months were brought to 12 with the introduction of January (Januarius dedicated to the god Ianus - Janus, god of the beginnings -) and February (Februarius destined for purification), which initially appeared in the queue to the other 10, only subsequently rearranged as initial months.
A beginning of the year more tied to the natural awakening of the Earth, which can also be found in other calendars such as the Chinese New Year (chūnjié - 春节) or the Persian New Year (Nawrūz, also known as Nowruz), although in different dates and ways. Even in the rest of Italy different adoption styles can be found (in Florence, for example, it began on March 25), but also oriented towards a spring period and only towards the 19th century, suitable for the date of January 1st.
Today's testimonies of the ancient celebrations, can therefore be the various brusàr marzo, ciamàr marzo, bàter marzo, which still take place today in some places in the Veneto. Specifically, bàter marzo (beat March), some trace it back to the oldest rite of Mamurio Veturio - the "old Mars" - which was beaten with long white poles and driven out of the city of Rome on 1 March. Since in ancient times Mars was not the god of war, but the god of vegetation, the ancient rites seem to refer to chasing away the old and dying god in favor of the nascent one, just as nascent is the vegetation that sprouts again after the winter.