File:Site of Bolingbroke Castle and Rout Yard, Old Bolingbroke - geograph.org.uk - 1555199.jpg

English: Site of Bolingbroke Castle and Rout Yard, Old Bolingbroke. Throughout their history, the castle and rout yard have been recorded many times. Two dates of note are 1949 and 1965, which gives a description of what was found and recorded. I managed to find this detail, but can't attribute it to anyone, as there is no mention.

"...The castle (at TF/349650), mainly celebrated for being the birthplace of King Henry IV, was placed in the Duchy of Lancaster in 1949. Only slight traces of masonry were visible through the turf at that time, although the shape of the moat was clear enough...

...six weeks of excavation at the castle in May-July, 1965...

...The area is approximately 200 yards (183 metres) square, with a bank and a ditch on three sides. This contains a curious and very conspicuous moated rectangular pond, omitted by Jared Hill on his map in 1718, but possibly already in existence. The enclosure has been known since at least 1600 as the 'rout yard', and we know from a survey of 1600 that it contains no buildings and that it was surrounded by a stake fence. The commission to the surveyors states that: 'There is adioynynge to the Mote of our said Castle a croft called the Castle yard or Raught yard, where unto all the wayfs and strayes within the Soke of Bolingebroke of anncient tyme have been used to be broughte.' In Lincolnshire dialect 'rout green' is a place where unclaimed cattle from the pound were put. No doubt as a result of intercommoning in the fens there were a great many stray cattle to be dealt with at Bolingbroke; the moat of the (?later) pond may have been intended as a drinking trough. The rout yard has been described as a bailey, but the use of such a term certainly misrepresents its real purpose..."

Well, that's one person's interpretation of the rout yard and seems reasonable, but when you read other's views, they also seem quite likely. Perhaps we'll never know its use and it may have had several, but whatever it was, it will soon have another metre of soil added to it and all from the castle moat. It will be interesting to see what grows there next year.