Wikipedia.
The oldest extant part of Windsor Castle is the central Round Tower, which dates from the twelfth century, although no visit would be complete without seeing St. George’s Chapel (fifteenth century, in the lower ward to the left) and the State Apartments (nineteenth century, in the upper ward to the right). Windsor is one of the more important royal castles, from which the current dynasty takes its name and derives its heraldic badge.
Wikipedia.
People forget, though, that Windsor was founded as a castle by William I shortly after the conquest – and now a vision of what that castle might have looked like has been produced. From the Independent:
the first Windsor Castle, built in 1071 to deter Anglo-Saxon rebels, is thought to have consisted of a multi-storey wooden keep on top of a large earthen mound flanked to its north and west by a two-and-a-half acre palisaded triangular courtyard (known as a bailey or ward).
It was probably built there for three very specific reasons. Being on a hill it was easier to defend and, because the Thames was unusually narrow at that point, it could be easily bridged. Indeed, it is now thought that the very first Windsor Bridge was probably built by William the Conqueror at the same time that the castle was erected. The third reason was its proximity to an Anglo-Saxon royal palace at Old Windsor – just one-and-a-half miles away.
The reconstruction of that first Windsor Castle (as it would have looked in around 1085) has just been published by the Royal Collection Trust (which manages most public access aspects of Windsor Castle) in a major new book – Windsor Castle: A Thousand Years of a Royal Palace.
Research – carried out by Dr Steven Brindle, co-author of the book and a leading expert on Windsor – has also generated the first ever archaeologically based modern reconstructions of Windsor Castle as it looked in 1216 and in 1272 (as well as in 1085). All three have just been published for the first time in the book.
Read the whole thing, which includes images from the new book.