This is the 6920th most frequent Polish word.
giedymin
"Giedymin" is a proper noun, referring to Gediminas, a historical Grand Duke of Lithuania.
Here, 'Giedymin' is used as a proper noun referring to a historical figure.
Giedymin był wielkim księciem litewskim.
Giedymin was the Grand Duke of Lithuania.
In this sentence, 'Giedymin' is used to inquire about the historical knowledge of the listener regarding this individual.
Czy wiesz, kim był Giedymin?
Do you know who Giedymin was?
Here, 'Giedymin' is used possessively to indicate the subject of the legends, reflecting on his attributes.