Since the 14th century craftmen’s guilds were significant brotherhoods who drove interests of their members. The big guild of Tallinn was an union of wealthy merchants. Their base was the Great Guild Hall in downtown, opposite the church of Holy Spirit. The building itself was built in 1407-1410 and is a well-preserved sample of Medieval construction.
Today the Great Guild Hall houses a museum presenting Estonia's history from prehistoric times right up to the end of the 20th century. Films and interactive displays show how people here lived, fought and survived over the last 11,000 years.
References: Tallinn Tourism
House of the Blackheads (Melngalvju nams) is a building situated in the old town of Riga. The original building was erected during the first third of the 14th century for the Brotherhood of Blackheads, a guild for unmarried German merchants in Riga. Major works were done in the years 1580 and 1886, adding most of the ornaments.
The structure was bombed to a ruin by the Germans June 28, 1941 and the remains demolished by the Soviets in 1948. The current reconstruction was erected from 1995 to 1999. Today the House of Blackheads serves as a museum and sometimes concert hall.