3 Grossus - Friedrich Kettler Mitau

Friedrich Kettler ruled Courland and Semigallia as a Polish-Lithuanian vassal duke, and his coinage reflects the awkward administrative reality of that arrangement — struck at the Mitau mint yet obligated to conform to the monetary standards set by the Polish-Lithuanian Commonwealth's reform edicts. The groszy issues of this decade were the bread-and-butter currency of Baltic trade, circulating across Livonian markets already disrupted by decades of warfare following the collapse of the Teutonic Order's successor state in 1561.

The decade-long span of this type suggests multiple die marriages rather than a single production run.