at the very end of the "brut tysilio" there appears a colophon ascribed to walter, archdeacon of oxford, saying "i […] translated this book from the welsh into latin, and in my old age have again translated it from the latin into welsh." on this basis, some took the "brut tysilio" to be, at one or more remove, the "very ancient book" that geoffrey claimed to have translated from the "british tongue". this claim was taken up by the archaeologist flinders petrie, who argued in a paper presented to the royal society in 1917 that the "brut" and the "historia regum britanniae" were both derived from a hypothetical 10th-century version in breton and ultimately from material originating in roman times, and called for further study.