II. Ulászló (Jagelló) Lithuanian prince and Polish king ruled from 1377 to 1434. During this time, he also brought about significant changes in coinage. In 1386, after the union with the Polish kingdom, he introduced the Polish coinage system in Lithuania. Lithuanian denars were then minted until 1430, but their weight and gold content were the same as Polish denars. In Poland, Ulászló reformed the coinage. In 1386, he introduced the solid gold zloty, worth 30 denars. The zloty remained the official currency of Poland in the following centuries. During the reign of Ulaszló, foreign masters played an increasingly important role in the Polish coinage. In 1392, German masters arrived at the Kassa mint, who combined local coinage traditions with German techniques. Ulaszló's coinage significantly contributed to the development of the financial system in Poland. The introduction of the zloty stabilized money and contributed to the development of trade. And foreign masters brought new techniques to Poland, which improved the quality of coinage. The most important types of Ulaszló's coinage were the gold zloty, ducat, half ducat, the silver denar, halfdenar, obolet and the bronze bracteate. The zloty and the ducat were the most important types of coinage during Ulaszló's reign. . The zloty formed the basis of the financial system in Poland, and the ducat was a valuable coin used in international trade. The denar was the most common currency in Poland even during the reign of Ulászló. However, its weight and gold content changed over time. The bracteate began to spread in Poland during the reign of Ulászló. It was a thin, light coin, usually struck in bronze.