Ash Wednesday 1777 was on February 12

Ash Wednesday is a Christian observance marking the start of Lent, a period of fasting, repentance, and reflection. On this day, ashes are typically applied in the shape of a cross on the foreheads of believers as a symbol of mortality and penance. It occurs 46 days before Easter Sunday.

Easter Sunday 1777 was on  March 30 

See Catholic Calendar for 1777

 
Falat Julian, Popielec