1 Mark - Gustav Vasa Bust type III

Gustav Vasa's mark coinage of the 1550s emerged from a deliberate debasement program — the king systematically reduced the silver fineness of Swedish currency across the decade to fund ongoing military and administrative costs, particularly the pressures of maintaining Swedish independence from Danish ambitions. The shift to .500 fine silver represented a significant departure from earlier, purer issues and was recognized as such by contemporaries.

The Bust type III designation distinguishes this from two earlier portrait varieties struck across the same reign, reflecting die recutting or workshop changes that numismatists have since used to sequence production within the 1557–1558 window.