The name of the holiday is taken from the Orthodox calendar - the date of honoring the memory of the martyr Blasius of Sebaste. Before the adoption of Christianity, the Slavs celebrated the holiday of the god Veles, the protector of cattle, on this day. Hence the date is also called the Cow Festival. On Vlasev's day, bazaars were opened where people went to sell and buy livestock. Weather signs for this day: if you noticed an abundance of snow on Vlasyev’s day, you were preparing for a warm May; warming during the day meant that the severe cold had already receded.