The slag material found at the archaeological site Rijselseweg in Ypres, Belgium consists of smithing slag, hammerscale and parts of the forge. The characteristics of the remains show that coal was used in a raised forge which probably stood nearby. Although the use of coal is quite probable for a late-medieval site like this, there aren't many other archaeological sites known where this is the case. Both iron and coal would have arrived at the site through trade with for instance Sweden and England. Since this part of medieval Ypres was known for its textile production, it is quite possible that the smith produced iron goods needed directly (scissors) or indirectly (horseshoes for transport) in the textile industry.