A while back I wrote a post about a knitting article on Suite101, with an adapted pattern for a medieval undershirt. For those readers who are members of Ravelry, there’s an interesting discussion about this garment here .
The pattern for these open crotch (oooh la la! those Victorians!) drawers is on the same site, with knitted lace edging and shaped legs. This pattern is original, from England. The knickers are open to ease the struggle of coping with long layers of clothing in the loo. Bagginess in the seat kept the opening from gapping. Of course, most drawers were probably sewn, from linen or cotton, rather than knitted.
Prior to the mid 19th century, “knicker(bockers)” were not commonly worn. The change in fashion to crinolines and hoop skirts, however, made them essential for modesty in case of a fall or a string wind.