In ancient Latvia, Tanis Diena was a sacred holiday held on February 17. It was held in honor of pigs and was transferred to the feast day of St. Anthony after Christianization.

A pig's head was placed atop a stone to protect from thunder and lightning. During the day, the townsfolk went to pig pens and sang sons glorifying the fertility of the pig. At lunch, a pig's head and feet were eaten and the remains were buried where the pigs would be herded the following year. Sewing or other needle-work was stricktly prohibited, as was drinking in the home. A foggy day indicated floods; a sunny day indicated a good barley crop; a dry day indicated drought, and vice versa.

Alternative: Tena Diena, Tunna Diena, Tenisa Diena, Cukausu Diena, Kunga Diena ("man's day")