These small, round bells are called "Schelle". Archaeologists also use this term to describe them. They are definitely from the late Middle Ages to the early modern period.
M. Kliewe 10.11.2023
Similar can be found on my favourite page about bells and chimes: Open link: www.ukdfd.co.uk There they date to the 13th-15th century, but the page only deals with the island.