'DE MONETA IN REGNO CURRENTE'. POLISH COINAGE OF KING CASIMIR THE GREAT ('De moneta in Regno currente'. Mennictwo polskie Kazimierza Wielkiego)
The unifying of Polish penny coinage was a long-lasting and multi-stage process that went simultaneously with the political integration of the kingdom that was being built from many duchies and lands in the fourteenth century. There are three sorts of larger coins of King Casimir the Great (1333-70): the Cracow groschen, the kwartnik, and the third coin whose original name remains uncertain. The latter was probably a fourth part of the Cracow groschen and was perhaps called 'small kwartnik'. The large kwartniks of unstable standard were coined in profusion. The king established their compulsory rate as a half groschen. Just after the king's death, in 1370, the governor of Great Poland devalued kwartniks to a quarter groschen, which caused commotion since these coins were actually not so much debased. The Cracow groschen (and small kwartniks) must have been struck earlier. It was probably at the latest in 1365, roughly simultaneously with a similar coinage in Teutonic Prussia. They might have been an unsuccessful attempt to introduce an autonomous groschen coinage, independent from Bohemian issuing authorities.
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