First records of fishing on Idrijca are almost as old as the first mentions of the town Idrija and of the mining activity in the town. Dr Marija Verbič, one of the best connoisseurs of Idrija history, researched and interpreted written sources of information dated in 15th century, originated from Čedad and Venice, in her doctoral thesis “Idrija mine until 16th century”. Among other she found that already in 1493 the Venetian Council of Ten attributed hunting and fishing rights on Idrijca and around the mining settlements to a German mining society (Kacijan Anderlein). These rights were otherwise in the hands of Tolmin counts as landlords of the Idrija region.
We can presume that in the 16th century fishing and hunting were unregulated as jurisdiction over them was not clearly delimited between the mine authorities, Tolmin landlord, and the provincial prince. In reality probably the quickest and more ingenious ones got the biggest prey. By all means poaching was a common practice.
Things changed after the state took over the Idrija Mercury Mine in 1575 and started to regulate fishing and hunting as well. In 1580, the Carolingian mining order applied to Idrija mine which established a thorough and radical reorganization of the company. Due to the oversized and uncontrolled fishing on waters of Idrijca Valley, the fisheries plummeted and therefore an attempt to regulate fishing was made with this codex.