A 1,000-year-old “Boleslaw sword” (i.e., from the glorious reign of Boleslaw the Brave; lived 967-1025 AD) dated to the beginning of the 11th century and believed to have belonged to a knight working for Poland’s first ever king, has been found at a “secret and hidden” location in Lower Silesia. In the Middle Ages, Lower Silesia was part of Piast-ruled Poland. The recently discovered Boleslaw sword, which is long (1 meter; 3.2 feet) and elegant, is thought to have belonged to a knight in Boleslaw the Brave’s service.

https://www.ancient-origins.net/news-history-archaeology/boleslaw-sword-0017086