1818 ALS IN OBERNDORF LAND SALZBURG ZUM ERSTEN MAL STELLE NACHT ERKLANG ZUR ERINNERUNG AN DAS JAHR -what is it

this is the reading from a 5 1/2 round metal piece that is very old and heavy. it has SF on the back and a building with angles on the front. I am trying to find out what it is. Any thoughts? thank you in advance...karen