There have been various names given to the ancient Polish Easter Monday custom of dyngus.  These include smigus, dzien swietego Lejka, oblej, or lany poniedzialek. They all refer to a ritual dousing with water.  The first known Polish writings on dyngus date back to the Middle Ages.  A Polish historian wrote of what he called the oblewania.  "It is the universal custom, among the common masses as well as among the distinguished, for the men to soak the women on Easter Monday.  On Tuesday, and every day thereafter until the time of the Green Holidays (Pentecost), the women doused the men."

Those who saw themselves as too refined above pouring water on some unsuspecting friend or lover would lightly pour rose water on their hands from a small bottle or flask.  Those who did not subscribe to delicasy and refinement approached it with gusto, dashing water from cups, glasses, and buckets right into an individual's face.  Very often men, women, nobles and peasants alike, didn't necessarily wait for their appointed day but grabbed whatever vessel was at hand and began throwing water at whomever was close at hand.  (from Polish Customs, Traditions & Folklore)

This hand carved and painted couple perfectly portray this annual custom that continues today.