The types of padlocks found in the chest are typical of archaeological finds from the Viking cities of Birka and Helgö in Lake Mälaren. They have also been found in other places in Europe where Vikings traveled. Similar locks are on display at the National Historical Museum in Stockholm.
The padlocks consist of two parts, a trapezoidal lock body of welded iron or bronze plate and a separate shackle. This is why they are often called (Viking) box padlocks. The shackle has ward springs on one leg. The other leg, which is somewhat conical, is inserted in a narrow, also conical tube attached on the outside of the lock. The top of the lock body has a hole for the shackle and the front has a T-shaped keyhole at the bottom. The key has a flat bit with notches for the guide pins and springs. To open the lock, insert the key in the keyhole and press upwards. This compresses the ward springs, allowing the shackle to be drawn out of the lock housing and outer tube.
Gotlandish keys
The two keys from the Mästermyr chest are Gotlandish, and their dimensions indicate that they were door keys. Their bows were designed for an easy grip, which helped when operating the somewhat tricky lock mechanism. Usually people did not lock the doors to their homes; locks were used only on chests and boxes and on larders where food was stored. This type of large key was inconvenient to carry around, so they were often hidden or stored in a locked chest.
In 1986, archaeologist Anna Ulfhielm analyzed a large number of Viking-Era keys from Gotland. All were made of cast bronze or iron, and were found with bronze buckles in the shape of animal heads (see sketch). This is also true of the four keys in her study that have a similar-shaped handle as those in the Mästermyr chest. The archaeologists dated these keys to the 10th century.
In her summary, Anna Ulfhielm stated that keys were the property of women in this era, as most keys were found in women’s graves. Keys also had a social element – the mistress of a house wore the keys hanging on her clothing as a personal attribute. This showed that she had power and responsibility for the farm.
The shape and ornamentation of keys, with or without locks, also helps archaeologists date them.