* Danzig (now Gdańsk, Poland) was a major trading city in the Hanseatic League, known for its shipbuilding and commerce, not horse racing.
* Jockeys are typically associated with horse racing, which was not a prominent sport in Danzig.
It's possible you might be thinking of something else, or the term "jockeys of Danzig" might be a misremembered or misunderstood concept.
Could you please provide more context or clarify your question?