Forres Castle was a fort and castle built near Forres, Scotland.
 The fort was destroyed in 850 by Vikings.
 Forres was created a royal burgh by King David I of Scotland in 1140.
 The castle, once a royal castle, was built as a motte and bailey castle and was strengthened in the 14th century.
 It was demolished in 1297 by the adherents of Wallace.
 King William the Lion and King Alexander II of Scotland visited and stayed at the castle.
 King David II of Scotland stayed at the castle in 1346.
 It was burned by Alexander Stewart, Earl of Buchan in 1390.
 Held by the Dunbars of Westfield until the 17th century, it fell into ruins.
 Nothing now remains above ground.
Guthrie is a village in Angus, Scotland, roughly at the centre point of the towns of Arbroath, Brechin and Forfar.
 The principal building in the village is Guthrie Castle, which has its own public golf course and is a popular venue for events such as markets, parties and weddings.
 The village of Guthrie is centered on the Guthrie parish church, containing the Guthrie Aisle, built in 1150.
Glen Eyrie is an English Tudor-style castle built in 1871 by General William Jackson Palmer, the founder of Colorado Springs.
 There are 17 guest rooms (12 Deluxe guest rooms and 5 premier guest rooms) in the castle, as well as 7 meeting rooms to include the Castle Great Hall (2200 square feet room in the castle that can hold up to 240 people) and 2 dining rooms in the castle (The Castle King James Hall has seating for 180 people and the Castle Music & Library rooms for seating for up to 58 people).
 This house was his and his wife's dream home and is near Colorado Springs in the northwest foothills just north of the Garden of the Gods rock formations (now a city park).
 After building a large carriage house, where the family lived for a time, Palmer and his wife Mary (Queen) Mellen built a 22-room frame house on the 800 acre estate.
 This house was remodeled in 1881 to include a tower and additional rooms, and made to resemble a stone castle in 1903, reminiscent of those native to England.
Guthrie Castle is a castle and country house in Angus, Scotland.
 It is located in the village of Guthrie, 10 km east of Forfar, and 29 km north-east of Dundee.
 The castle dates back to the 15th century, although much of the present building is of 19th-century origin.
 It is now a private house.
Montrose Castle was a 12th-century castle built in Montrose, Angus, Scotland.
 Montrose was created a royal burgh by King David I of Scotland in the 12th century.
 The castle, once a royal castle, was built as a motte and bailey castle.
 King Edward I of England accepted John Balliol's surrender of Scotland at the castle on the 10 July 1296.
 The castle was destroyed by William Wallace in 1297.
 The castle was noted to be in ruins in 1488.
 Nothing now remains above ground.
Castell Coch (] ; Welsh for Red Castle ) is a 19th-century Gothic Revival castle built above the village of Tongwynlais in South Wales.
 The first castle on the site was built by the Normans after 1081, to protect the newly conquered town of Cardiff and control the route along the Taff Gorge.
 Abandoned shortly afterwards, the castle's earth motte was reused by Gilbert de Clare as the basis for a new stone fortification, which he built between 1267 and 1277 to control his freshly annexed Welsh lands.
 This castle was likely destroyed in the native Welsh rebellion of 1314.
 In 1760, the castle ruins were acquired by John Stuart, 3rd Earl of Bute, as part of a marriage settlement that brought the family vast estates in South Wales.
Shea’s Castle, also known as Sky Castle and Castle Ranch, is a private castle built in 1924 by the developer Richard Peter Shea.
 Shea, a New Yorker, moved to the dry climate of Southern California in hopes of improving the health of his wife, Ellen.
 Shea made his fortune developing Hancock Park in Los Angeles.
 He spent two years building the castle on about 1,500 acres (6 km²) of land in the Antelope Valley, just west of Lancaster and just south of the Antelope Valley California Poppy Reserve.
 The cost of building the castle (at the time) was $175,000.
Santa María de la Cabeza castle is a colonial castle built in the seventeenth century by the Spanish monarchy in the center of the city of Cumaná, Venezuela.
 It was built as a replacement for the San Antonio de la Eminencia castle.
 Its construction was ordered by Sancho Fernando de Angulo y Sandoval, governor of the Province of Cumaná.
 The building was designed using the trace italienne style popular during the seventeenth century, with a proportional geometric floor design.
 Bastions were used as the main defensive elements.
 The castle housed a garrison of 250 soldiers, and was the seat of government for the Province of Cumaná.
Drzewica Castle - a Gothic-Renaissance castle built between 1527 and 1535 by Archbishop of Gniezno Maciej Drzewicki.
 The Archbishop built the castle on the peripheries of the town, by the river Drzewiczka and encircled the fortress with moats, separated by a bulwark.
 The building's plan is based on a regular rectangular shape.
 Its defence systems are based on four square towers located in each corner of the castle.
 The building burned down in 1814, remaining a well preserved ruin.
 Thus, the castle did not undergo any later modifications, remaining one of Poland's best preserved residences from the first part of the sixteenth-century.
Dunderave Castle is an L-plan castle built in the 16th century as the Scottish seat of the MacNaughton clan.
 The castle lies on a small promontory on the northern shores of Loch Fyne, around 5 km north-east of Inveraray, Argyll.
 The castle is in use as a residence.
 The present castle was built after their previous castle was destroyed following a Plague infection.
 The old castle, and remnants of McNaughton crannógs, can still be seen on the lochan known as the Dubh Loch at the head of Glen Shira.

Question: When was the castle built that is the principle building of Guthrie, Angus?
Answer: 15th century