Frankopan Castle was raised by Croatian noble family of Frankopan through several centuries and several generations. After the death of the first Count (knez) of Krk Dujam I Krčki, his sons continue to dominate over the island and the town of Krk. They left first architectural traces in the town of Krk. The oldest part of fortification is the square tower with the diocese, in which Frankopans courtroom was located. The inscription on the lunette over the entrance confirms that the building was raised in 1191, during the time of Bishop John and counts Vid I and Bartol I (Dujam's sons), with the help of the entire municipality.
The round tower on the northern corner of the castle with a transversely extended lower part, was built after the square, probably in the 13th century. It was restored around 1480, and again around 1600. On the tower there is bricked inscription Aureae Venetorum libertati with lions of St. Mark, which dates from 1500. This cylindrical tower has two floors and attic. On the ground floor once there were two doors, one open to the Kamplin, and the other toward the interior of the castle. On the eastern part of the castle, overlooking the sea there is still a square tower, while on the western part of the castle there was a sentry box for guard. Within the complex there was space for soldiers. It is not known precisely when, but the entire complex was completed before 1348.References:
German crusaders known as the Livonian Brothers of the Sword began construction of the Cēsis castle (Wenden) near the hill fort in 1209. When the castle was enlarged and fortified, it served as the residence for the Order's Master from 1237 till 1561, with periodic interruptions. Its ruins are some of the most majestic castle ruins in the Baltic states. Once the most important castle of the Livonian Order, it was the official residence for the masters of the order.
In 1577, during the Livonian War, the garrison destroyed the castle to prevent it from falling into the control of Ivan the Terrible, who was decisively defeated in the Battle of Wenden (1578).
In 1598 it was incorporated into the Polish-Lithuanian Commonwealth and Wenden Voivodship was created here. In 1620 Wenden was conquered by Sweden. It was rebuilt afterwards, but was destroyed again in 1703 during the Great Northern War by the Russian army and left in a ruined state. Already from the end of the 16th century, the premises of the Order's castle were adjusted to the requirements of the Cēsis Castle estate. When in 1777 the Cēsis Castle estate was obtained by Count Carl Sievers, he had his new residence house built on the site of the eastern block of the castle, joining its end wall with the fortification tower.
Since 1949, the Cēsis History Museum has been located in this New Castle of the Cēsis Castle estate. The front yard of the New Castle is enclosed by a granary and a stable-coach house, which now houses the Exhibition Hall of the Museum. Beside the granary there is the oldest brewery in Latvia, Cēsu alus darītava, which was built in 1878 during the later Count Sievers' time, but its origins date back to the period of the Livonian Order. Further on, the Cēsis Castle park is situated, which was laid out in 1812. The park has the romantic characteristic of that time, with its winding footpaths, exotic plants, and the waters of the pond reflecting the castle's ruins. Nowadays also one of the towers is open for tourists.