Margaret II, Countess of Hainaut and Holy Roman Empress and her son William I, Duke of Bavaria, sign a peace treaty ending the Hook and Cod wars.

Margaret II of Avesnes was Countess of Hainaut and Countess of Holland from 1345 to 1356. She was Holy Roman Empress and Queen of Germany by marriage to Holy Roman Emperor Louis IV the Bavarian.

William I, Duke of Bavaria-Straubing, was the second son of Emperor Louis IV and Margaret II of Hainaut. He was also known as William V, Count of Holland, as William III, Count of Hainaut and as William IV Count of Zeeland.

The Hook and Cod wars comprise a series of wars and battles in the County of Holland between 1350 and 1490. Most of these wars were fought over who should hold the title of "Count of Holland". The Cod faction generally consisted of the more progressive cities of Holland. The Hook faction consisted for a large part of the conservative noblemen.

December 17 is the 351st day of the year in the Gregorian calendar; 14 days remain until the end of the year.