A classic and standard text. Although earlier work had been done by Ella Armitage and others this is the Text which debunked the idea exposed by G.T.Clark that castles (in particular mottes) were Saxon. About half the book is descriptions of specific castles.
Much of the work was published in;
Armitage, Ella, 1904, English Historical Review Vol. 19 pp. 209-245, 417-455
a critical review was published the next year
Davies-Pryce, T., 1905, English Historical Review Vol. 20 pp. 703-711
and, in same volume responded to
Armitage, Ella, 1905, English Historical Review Vol. 20 pp. 711-18
Further information, comment and critique of this seminal text can be found in:
Hamilton, Bob, 2000, 'Castles and the Children of Alfred' Assemblage No. 5 online copy.
Mercer, David, 2004, Castle studies in England and the making of archaeological knowledge (Cambridge University PhD Thesis)
Fyfe, Morag, 2012-13, 'Ella Armitage and Norman Castles 100 years ago' The Castle Studies Group Journal Vol. 26 p. 216-29
Hulme, Richard, 2012-13, 'A Hundred Years of Castle Studies: The enduring influence of Ella Armitage' The Castle Studies Group Journal Vol. 26 p. 231-244
Guy, Neil (ed), 2012-23, 'Early Norman Castles of the British Isles - Errata and Corrigenda' The Castle Studies Group Journal Vol. 26 p. 245-252 (Copy of Armitage's manuscript notes for an intended revised edition) online copy
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See also the Ella Armitage page of the Castle Studies Group Website.