The style of castle which I call "courtyard" and others may call "rectangular", or even "enclosure", is quite a common one, but difficult to define exactly. So perhaps it is better to try and describe this type of castle in terms of what features it doesn't have, rather than those that it does have.

It shouldn't have a motte, for starters, otherwise it would be a motte and bailey or just a motte castle. Neither should it have a massive rectangular Norman keep. Or an equally massive keep-gatehouse.

What it should have is a single curtain wall, with a few towers perhaps, and maybe a simple gatehouse. Within the enclosure there should be a hall, kitchen, chapel, stables and other ancillary buildings.

If this sounds suspiciously like a fortified manor-house, you could be right. You could say that a courtyard castle is a more elaborate version of a fortified manor-house.

A case in point is Baconsthorpe Castle in Norfolk. Study the aerial view...

To illustrate the link between fortified manor-house and courtyard castle, and give you some idea of how the one may have evolved into the other, let us look at the somewhat notorious Castle Scrunge.

Sir Albert Scrunge, having been mistaken for someone else by King William I, is given a small parcel of land and builds himself a manor-house.

The house is a modest wooden affair with hall and solar. Being pious, Albert builds a chapel, and being practical, and hungry, constructs a number of other buildings. All these are also in timber.

For protection, the buildings are surrounded by a stout wooden palisade and further enclosed by a water-filled moat.

So, it's not just a fortified manor-house, it's a moated manor-house as well!

Here is a plan of Albert's house, which he calls Castle Scrunge.

In the middle of the 12th century, Albert's son, Basil, is getting fed up with the accommodation, and having some spare funds, does a spot of home improvement. He rebuilds the house and chapel in stone. Having had the odd argument with the neighbours, he also replaces the timber palisade with a stone wall.

The solar now has two floors, and to make life easier, Basil adds a stair turret.

As the 13th century dawns, Basil's son, Cuthbert, has a bit of a win on ye olde lotterye and decides on some further improvements to the family seat. He rebuilds the curtain wall, making it much thicker and higher, and adds a number of towers, in the fashionable square style.

The corner towers and the towers of the gatehouse are built with four walls, but the other towers are left open at the back. This is because space is limited and the money ran out.

The simple fixed wooden bridge over the moat is also replaced by a drawbridge.

In the middle of the 13th century dawns, Cuthbert's son, Desmond, worms his way into the king's favour and finds that he can afford to carry out yet more improvements. He enlarges both the house and chapel.

Both house and chapel have more elaborate windows and the house now boasts several fireplaces, with chimneys, and garderobes. Thus the house is warmer in winter and much less smelly in summer.

You will notice that the resident priest now has his own humble abode, near the chapel. He had previously slept in the hall with the rest of the household and had kept everyone awake with his snoring.

In the early part of the 14th century, Desmond's son, Ebeneezer, is obliged, by a fatal combination of woodworm and fire, to finally rebuild the kitchen, granary and stables.

Notice that the kitchen boasts two fireplaces and an oven.

You will also notice that the granary block has no windows. This is a deliberate ploy to protect the valuable foodstuffs, wine, beer, etc., from the effects of sun, wind and thieves.

Towards the end of the 14th century, Ebeneezer's son, Fortinbras, falls out with the neighbours again in a fairly serious manner. He rebuilds the square towers as round towers, by adding masonry to the outside faces.

He also converts some of the hall and solar windows into arrow-loops.

In the middle of the 15th century, Fortinbras's son, Gilbert, is in serious financial difficulties. Nevertheless, he feels obliged to do something to the family seat.

A loan at eye-watering interest rates allows him to remodel the gatehouse towers to match the others.

In case you're wondering, yes, it was the neighbours who lent him the money.

At the start of the 16th century, Gilbert's son, Hercules, gets the worst possible news. The king, Henry VII, has decided to pay him a visit.

At the risk of bankruptcy, Hercules constructs a whole new set of rooms, complete with elaborately carved fireplaces, fancy windows and a newel stair in the north-east tower.

Just as the work is completed, Hercules gets a message to say that the king has changed his mind and is going to see his Auntie in Aberystwyth instead.

Having filed for bankruptcy, Hercules was obliged to sell Castle Scrunge to the neighbours. Over the following centuries it gradually deteriorated until all that is left today are the remains of the two garderobe towers.

One of these is home to a local tramp who insists that his name is Zachariah Scrunge, although nobody believes him.