The most prominent building on the Square was built for William Thorne, in 1872. ( Thorne was a quarry owner and operator of the horse-drawn railway to Fremington Quay.) His new house was constructed of brick with decorative stone details. It is said that Thorne never actually lived in the house. The house was a sizeable building, with a grand staircase and 15 servants' bells in the back corridor.
The house was bought by William Rock (Barnstaple benefactor) in 1887, to house the North Devon Athenaeum, a free library and Museum. It was opened to the public the following year. The Athenaeum inherited the collections of the Barnstaple Literary and Scientific Institution - founded by William Rock in 1845 and continued to accumulate a wide variety of objects, papers and books. From 1956, the Athenaeum shared the building with the local branch of the County Library Service. Local people remember coming to the Athenaeum to do their homework. In 1988, North Devon District Council bought the building. The Athenaeum, its collection of documents and the County Library moved to purpose-built premises in Tuly Street. Many of the Athenaeum's objects remain in the Museum of Barnstaple and North Devon. These include the rocks and minerals in the first gallery, local paintings and part of the pottery collection.
