What is the origin of a foreign coin?

there is a heavy featured, large busted woman on the front with the letters R*IMP*HU*BO*REG on the left of the woman's head, and M*THERESIA*D*G on the right of her head. On the back of the coin, silver, is a large family or royal crest with a crown at the top, two eagles facing out. The letters on the left of the crest are BURG*CO*TYR*1780. The letters on the right of the crest are ARCHID*AVST*DUX