You asked about the history of Windsor chairs (image 1) and Scandinavian stick-back chairs, so let's look at these icons of vernacular design. Windsor chairs always seemed to be the ultimate colonial American chair — for me they evoke captains' houses on the New England coast, or the principal's book-lined leather-desked office at a prep school. But the chair's origins can actually be found in England, around — you guessed it — Windsor.
We may need Johnny to further clarify the construction of the Windsor chair, but basically it is a form of stick chair — as opposed to a joined chair — where round tenons are fitted into sockets. In Windsor chairs, the seat is made of one piece of solid wood, and the back spindles are separate from the legs. One idea for the origins of the Windsor chair is that it is based on the construction of your simple everyday milking stool, and it is certainly related to the crude stools you can see in sixteenth-century depictions of peasant life (image 2), which in Elizabethan England were known as "stake stools."
The first English examples of the Windsor chair appeared around the early 1700s. They were typically used as outdoor furniture, and were usually painted — partly to disguise differences in the woods used, and partly to protect the wood from the elements. The new chair type soon made its way to the colonies, appearing in Philadelphia around 1730, where local craftsmen made variations to the form, developing the Windsor chair into an American classic. Varieties include the sack-back (image 1), the low-back or captain's chair (image 3), the fan-back (image 4), and the loop-back (image 5). Windsor chairs can be found with or without arms.
With lathe-turned or hand-whittled legs and spindles, the Windsor chair was never a very fancy or expensive chair, but it was still a favorite among the wealthy merchant classes, maybe because its scooped seat and angled back made it much more comfortable than traditional ladder-back chairs. Even in somewhat lavish settings, like Thomas Jefferson's Monticello (image 6), the Windsor chair still carried connotations of vernacular style and traditional handcraft, which made it ripe for a comeback in the late nineteenth century, with the Arts & Crafts movement flourishing in England and America.
You can also see the influence of the Windsor chair in Scandinavia, where there was a long tradition of woodworking, and therefore a long tradition of vernacular wooden chairs. We start seeing a lot of Windsor-type chairs in Sweden around the late nineteenth century (image 7) — not because they didn't exist beforehand, but because the more fashionable Swedish furniture before then ran more towards French eighteenth-century precedents (Gustavian furniture is basically a variation on contemporary French design). When designers became influenced by the Arts & Crafts movement in England, they brought the stick style back into fashion; its simple, comfortable, light construction and natural wood finish also helped it fit perfectly into the modern Scandinavian aesthetic (which I discussed briefly in this post on IKEA). During the twentieth century, Scandinavian designers were inspired by the Windsor chair, producing new, modern variations on it that have since become design icons (images 8-9). The latest example may be Lina Nordqvist, whose 'mismatched' set of Windsor-type chairs is getting lots of notice around the internets these days.
(Images: 1 An antique sack-back Windsor chair in a Jeffrey Bilhuber interior, photo by Don Freeman for House Beautiful; 2 Pieter Bruegel the Elder's "Peasant Wedding" (1568), Kunsthistorisches Museum, Vienna; 3 Captain's Chair, also known as a low-back Windsor chair, photo by Chuck LaChiusa, from his highly informative website; 4 Fan-back Windsor chair, Chuck LaChiusa; 5 Loop-back Windsor Chairs in a T. Keller Donovan Nantucket interior, photo by John Gould Bessler for House Beautiful; 6 Entrance Hall at Monticello, photo by Robert C. Lautman for the Thomas Jefferson Foundation; 7 Hanna Hirsch-Pauli's "Breakfast Time" (1887), at the Nationalmuseum, Stockholm; 8 Carl Malmsten's Lilla Åland chair (1942), from the Malmstenbutiken; 9 Hans Wegner's Peacock chair (1947), via scandinaviandesign.com 10 Lina Nordqvist Family Chairs.