Towards the 11th century Cavriana became one of the properties of Canossa and it is in this period that the first fortification was probably built. Subsequently to the Canossa the ownership of the village passes to the free Municipality of Mantua that, to defend the boundaries from the growing power of the Municipality of Verona, grants it to the family of the Riva with defensive tasks but, in the second half of the XIII century, they are supplanted by the emergent family of the Bonacolsi, who in turn, in 1328, were replaced by the Gonzagas with the election to Imperial Vicar of Luigi Gonzaga by the Emperor Ludwig IV the Bavaro. With the increase in danger due to the neighboring Visconti, the castle is reinforced with high walls that surround the entire village, while the fortress has at that time four towers at the corners; in the second half of the 14th century clashes with the Visconti are frequent and in 1383 he moved to Cavriana Francesco I Gonzaga to escape the plague and died here in 1407.
Between 1458 and 1461 the fortress was strengthened and modified to a design by Giovanni da Padova to adapt to new war techniques and the advent of cannons, it is also surrounded by a system of ditches. In 1501 Francesco II Gonzaga, at the time military commander in the pay of the Serenissima, armed the fortress of artillery.
In the first decades of the 17th century the Rocca Castello di Cavriana appears to be the largest of the state, is then attacked and occupied with partial demolition, so that in a census of the defensive structures of 1650 the castle is decayed. In 1708 the Gonzagas fall and the Austrians are not interested in rebuilding the fortification, so much so that in 1771 they ordered the demolition.
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.