Knowledge about old weapons from Polish arsenals is still so fragmentary. Plenty of objects disappeared during centuries. But it is true, that Polish kings, dukes, magnates, the nobility and burghers possessed many types of weapons at the highest level, as evidenced by many former inventories. These days is possible to identify, for example, just four armours of Polish kings; one belonged to Zygmunt II August (1548-1572), two to Henryk III (Henri de Valois, 1573-1574), one to Stefan Batory (1575-1586) and some others belonged to Polish magnates (from Radziwiłł and Zamoyski’s arsenals). The same situation is with fire- and pole-arm, melee weapons, artillery, etc. Particularly well-known is weapon from Nieśwież arsenal, preserved in many collec-tions all over the world. The author made an effort to search lost arms, and this article shows effects of that job, introducing some examples of weapons from Radziwiłł Family’s arsenal and other Polish in origin, from collection in the USA and the United Kingdom.