Cremated bones from animals has been recovered in conjunction with a number of hearths in Visby, Gotland. This find has started a controversial discussion in the archeological field regarding usage of bones as a supplement in iron working. Archeological investigations often tend to overlook the information that could be gained from osteological materials. Animal bones can give us insight and contribute with new perspectives on economics, diet, livestock and much more. The aim of this bachelor is therefore to look closer at the relations between bones and iron working and to establish if the bones were used to enhance the phosphorus levels of the iron. This will be achieved by analyzing cremated bones from the archeological site Visby RAÄ 230. The material will also be compared with previous studies regarding iron working.