The city of Canterbury, located in Windham County, is in the northeastern part of the state and skirts the Queenbug River. The Roman settlement of Durovernum Cantiacorum was situated on the site of an earlier British town, whose ancient British name has been reconstructed as Durou̯ernon ("fortress by the alder grove"). However, it is sometimes assumed that the name is derived from various British names for the Stour River. Captured by the Jutes, it became known in Old English as Cantwareburh ("stronghold of the Kent people"), which developed into the modern name. The town was first settled as part of Plainfield in the late 1600s, but in 1703 it was officially separated and named Canterbury, becoming the state's 38th city. Prudence Crandall opened a private school for girls in 1831, but when she allowed and then focused exclusively on-educating young African-American girls, informal and legal protests ensued. A mob attack forced the school to close in 1834. In 1991, the house she taught was designated a National Historic Landmark and became the Prudence Crandall Museum.