What Happened in 1257
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- Jun 5 Kraków, Poland, receives city rights.
- Oct 14 Przemysł II, King of Poland (1295-96), born in Poznań, Kingdom of Poland (d. 1296)
- Jun 4 Duke Przemysl I of Poland
- Dec 24 John I, Count of Hainaut (1246-57), dies at 39