Year 1257 (MCCLVII) was a common year starting on Monday (link will display the full calendar) of the Julian calendar.
Robert de Sorbon founds the Collège de Sorbonne at Paris, France giving a formal college (and still-common name) to the already existing University of Paris in France.
Matthew Paris, English historian, personally interviews King Henry III of England for an entire week while compiling his major work of English history, Chronica Majora.
King Henry III of England orders the production of a twenty pence English coin of pure gold, the first high-denomination coin minted in England and the first to use gold. Unfortunately for King Henry, the bullion value of the coins is about 20% higher than the nominal face value, leading to poor circulation as coins are melted down by individuals for their gold content.
The second Genoese War breaks out between Genoa and Venice in Outremer, known as the War of Saint Sabas.
The city of Kraków is rebuilt by Boleslaus V of Poland after being nearly destroyed in the Tatar invasions in 1241 and is granted Magdeburg rights on June 5.
Władysław Opolski founded the Franciscan monastery in city Wodzisław Śląski. Before this date Wodzisław was granted Magdeburg rights (1246-1257).
The Japanese Kōgen era ends, and the Shōka era begins.
The Mongols take Dai Viet (northern Vietnam).
Lambsar Castle in Persia is destroyed by the Mongols.
Founding of Aberdeen Grammar School in Scotland.
Eruption of the Samalas Volcano on Lombok Island, Indonesia.
Epirote–Nicaean conflict.
Karelians made an expedition to Sweden which lead Valdemar to request Pope Alexander IV to decleare a crusade against them. This resulted to the third Swedish crusade to Finland.
Birth of Eli the Prophet, a Jacobist prophet and the final prophet of Allah, in Bethlehem
October 14 – Przemysł II, king of Poland (d. 1296)
Beatrice of Burgundy, Lady of Bourbon (d. 1310)
April 28 – Shajar al-Durr, sovereign sultana of Egypt.
June 4 – Duke Przemysł I of Greater Poland
August 15 – Saint Hyacinth
December 24 – John I, Count of Hainaut (b. 1218)
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