Modern arsenals stored valuable objects of various types, but undoubtedly military items dominated. In some, such as the one in Warsaw, it was possible to come across, for example, a prosthetic forearm, also known as a mechanical hand.

It seems that one of the earliest references mentioning prosthetic hands is a passage from Pliny the Elder's encyclopaedia Natural History from 77 AD. Of course, earlier accounts are known, but these come from archaeological sources or cave paintings. Meanwhile, in his encyclopaedia, the author mentions the loss of a hand by a Roman commander during the Second Punic War, who was able to return to the battlefield thanks to a prosthesis he received. In Poland, there is an early account by Gall Anonim, describing in his Chronicles the handing over of a "golden arm" by Bolesław the Wrymouth to the voivode Zelislaw ("There the commodore Zelislaw lost his arm, in which, holding a shield, he covered his body with it, but immediately avenged its loss valiantly by killing the one who had cut it off. Prince Bolesław, in turn, to honour him, returned his golden hand for his body").

The Renaissance brought developments in science, including advances in surgery, prosthetics and orthotics. Iron prostheses were then created, both of the hand as well as of the arms and forearms. They were created in a shape resembling a human limb; they were equipped with an elbow joint that allowed them to bend and, by releasing a special lock with the push of a button, to straighten. However, they were still quite heavy and required control from the unaffected hand, which was sometimes problematic. In addition, upper limb prostheses were among the products that wealthy people could afford, which is why the number of prostheses preserved is smaller than that of lower limb prostheses.

Over time, i.e. from the 17th century onwards, they began to be improved through the use of steel and copper, as well as through changes in design. The aim of these modifications, apart from increasing functionality, was also to reduce the weight of the prostheses, as the previous ones - although they restored the soldiers' ability to hold weapons - still caused problems in handling. The design improvements continued to progress and, as a result, began to broaden their audience. In the early years of the 17th century, an Italian physician, Giovanni Tommaso Minadoi, designed a prosthesis for an amputee who had not served in the military.

An extremely interesting object is a prosthetic forearm and hand, also known as a mechanical hand, kept in the Livrustkammaren (Royal Armoury) in Stockholm. It is designed for a person who has lost their left hand. It was made between 1600 and 1620 from steel painted black. It is 440 mm long, 125 mm wide and weighs 1480 g. The 95 mm wide hand was fitted with five movable fingers, and a button at the top of the hand allows the fingers to be positioned as desired. The fingers were attached to a special joint, on internally attached knuckles. The palm, on the other hand, was connected to a forearm cuff. And two pairs of hinges have been placed on the openwork sleeve.

In the inventories of the Stockholm Royal Armoury, the object was recorded several times. The first information is from 1683, when it was listed as one of the objects brought from Poland. It is also known to have been used later by Carl Gustaf Güntherfelt (1672-1738), Charles XII Wittelsbach's horseman, who lost his arm at the Battle of Kliszów (1702). Some sources report that Güntherfelt lost both arms in the battle, but this does not seem likely, as he accompanied Charles XII in the field in the following years.

The next mention of the object comes from an inventory of 1748, a decade after the death of the royal horseman. It was then noted under number 513: 'En Järnhand med Konst giord, för en lahmskuten at bruka' [An iron hand with art given, for a lame man to use]. Two more references, this time from the 1803 and 1813 inventories, also under the number 513. report "1 st Jern hand nyttjad af Gÿnterfeldt Tid. inv. no.: 513" [1 piece of iron hand used in Gÿnterfeldt's time inv. no.: 513]. Thus, it is known that the object was loaned to the King's Conjurer after he lost his hand, and after his death the prosthesis was returned, presumably by his family, to the Royal Armoury. The object is currently on display in the Stockholm Armoury.