question: When was the castle built that is the principle building of Guthrie, Angus?
answer: 15th century
context: Title: Shea's Castle
  Passage: 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.
  Title: Guthrie, Angus
  Passage: 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.
  Title: Guthrie Castle
  Passage: 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.
citations: Guthrie, Angus Guthrie Castle