The lands of Mugdock were a property of the Grahams from the mid-13th century, when David de Graham of Dundaff acquired them from the Earl of Lennox. It is possible that the castle was built by his descendant, Sir David de Graham (d. 1376), or by his son in 1372. In 1458, the lands were erected into the Barony of Mugdock. Later, in 1505, the Grahams were created Earls of Montrose.
The original castle may have been shield-shaped on plan, comprising towers arranged around a courtyard, and linked by curtain walls and ranges of buildings. The castle stood on a natural, steep-sided mound formed of hard volcanic rock. Of the early castle, only the south-west tower remains complete, and forms the most recognisable feature of the ruins. The narrow tower is of four storeys, with an entrance on the first floor, accessed via exterior steps on the east side. Inside the basement is vaulted, and a single room occupies each storey. On the outside, a line of corbels projects the two upper storeys out from the lower levels, giving the tower a distinctive 'top-heavy' appearance. The only other remains are the basement of the north-west tower, part of the gatehouse, and linking sections of curtain wall.
The castle was extended in the mid-15th century, probably around the time that the barony was created. An outer wall was built to enclose the majority of the mound as an outer courtyard. This courtyard had its main entrance to the south, adjacent to the south-west tower. Inside the courtyard are the ruins of various stone buildings, mainly dating from the 16th century. These include a chapel at the north extent of the courtyard, and a domestic range at the south-west. Much of the outer curtain wall has also disappeared, although the southern section remains.
A terraced walled garden, incorporating a summer house, was built to the east of the castle in the 1820s. Local historian John Guthrie Smith (1834–1894), a relative of the Smith family of nearby Craigend Castle, leased the house from 1874. He had the 17th-century mansion demolished, and commissioned a Scottish baronial style house to be built in the ruins of the old castle. It was designed by architects Cambell Douglas & Sellars, and was extended to designs by James Sellars in the 1880s.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.