Allen was the son of
George Baugh Allen. He was educated at
King's College School,
Rugby and
King's College London. In 1867 he was articled to
George Fosbery Lyster, engineer in chief to the
Mersey Docks and Harbour Board, with whom he remained until 1870. He was next employed as resident engineer to the Persian railways of
Baron de Reuter and afterwards in supervising the construction of docks at
Leith and at
Boston, Lincolnshire. Meanwhile, Allen was interested in archaeology; and he spent the rest of his life on it, and particularly on the study of prehistoric antiquities and of pre-Norman art in
Great Britain. His earliest contribution was to
Archæologia Cambrensis ("A description of some cairns on Barry Island"), appearing in April 1873; he joined the
Cambrian Archaeological Association in 1875, was elected a member of the general committee in 1877, became one of two editors of its
Journal in 1889, and was sole editor from 1892 until his death. Having begun with the antiquities of
Wales, Allen from 1880 gave attention to those of
Scotland also; in 1883 he was elected fellow of the
Scottish Society of Antiquaries, and in 1885 was
Rhind Lecturer in archaeology in the
University of Edinburgh. In
England, he became fellow of the
Society of Antiquaries of London in 1896, editor of the
Reliquary and Illustrated Archæologist in 1893; and
Yates Lecturer in archæology in
University College, London, for 1898. Allen was unmarried, and during his later years made his home in London, where he died on 5 July 1907. ==Works==