First mentioned as Soban, Sobień Castle was a Royal castle guarding the merchant route along the San River. The castle was built by order of King Casimir the Great in 1340. In 1389 Władysław II Jagiełło conferred the castle to a noble family of Kmita.
The castle was destroyed in 1474 and again in 1512 by Hungarian forces. In 16th century the Kmita family sold the estates and the castle to Stadnicki family, who held it until 1713.
References: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.