Dutchess Ofka (a diminutive of Euphemia) is a figure historically remembered as an important force in the area, credited with founding the first public hospital. She was also a very attractive woman, drawing the attention of many suitors, though none caught her interest until she accidentally met John the Good. He managed to win her heart, and the couple became engaged, planning their wedding to take place just after Kupala Night. Sadly, the ceremony never happened, as Ofka inexplicably broke off the engagement. To symbolize the end of their relationship, she threw her ring from the Piast Tower. The ring was lost in the dark recesses of the dungeons below and was never recovered. John was so heartbroken that he ordered her imprisonment. Unable to move on, he never married and left no heir to the throne. Since then, on every Kupala Night, one can encounter Ofka’s ghost beneath the Piast Tower, searching for the lost ring. Though the truth may never be known (John the Good may have been unable to have children), it is said that whoever finds the ring will be immune to illness, will learn the answers to all their questions, and will never know poverty.
Source: Opole z Sercem. (2018, July 11). 5 najciekawszych legend o Opolu. https://www.opolezsercem.pl/2018/07/5-najciekawszych-legend-o-opolu.html
