One of the earliest examples of a sofa, the Knole Sofa was originally an upholstered, more casual throne on which the monarch sat to receive visitors. It is associated with and named after one of the great houses of England, Knole House, located in Kent and owned by the Sackville-West family since 1605.
Below is the original Knole sofa in Knole House, which is part of the National Trust. The design is marked by a hinged back and sides which can fold down. The tops of the back and sides have finials and when the back and sides are in an upright position, they are held in place by braided cord, often with tassels, wrapped around the finials.
For fans of "Downton Abbey," here is a screen cap from the series of a Knole House sofa in the library; behind it we can see Mr. Carson (played by Jim Carter). We have seen Lord and Lady Grantham sit here often. The next photo shows a view of the antique Knole sofa in the library of Highclere Castle, the real life castle which serves as the setting for "Downton Abbey."
Although the Knole sofa originated in the early part of the 1600s and was traditionally upholstered with tapestry material...
...it can be used successfully in contemporary rooms. Here is a Knole sofa upholstered in a modern fabric. It works quite well with the lime green bolster pillows!
And here is a beautiful example of how to reference a period without copying it. Designer Orlando Diaz-Azcuy places two Knole sofas by a fireplace. In spite of the ancient origins of this sofa, the simplicity of the room and the white linen upholstery makes the scene feel contemporary and clean-lined. This reminds me of Design Mantra #1, previously here: Contrast brings interest!