The earliest traces of human settlement on the Sulzbach castle hill have been dated to the Late Hallstatt or Early La Tène culture. The medieval settlement was built first in the 8th century or early 9th century. The partially stone-made castle was built there in the 9th or 10th century. In 1003 the castle was moved to the Nordgaugrafen family by Henry II. The medieval castle was rebuilt from 1618 to the Renaissance style. Today the original tower from c. 1100 exists.
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.