In one sense I did not walk the Wall alone. I had two companions, William Hutton and Dr. Collingwood Bruce. The latter was represented by his _Handbook_ on the Wall, which was first published in 1863, and which has proved its value by having appeared, in seven successive editions, as the standard work on the subject. Dr. Bruce and Mr. John Clayton will always be remembered as the great pioneers of practical research on the Wall. {xvi} I owe much to the kindness of Mr. F. Gerald Simpson, who hopes to return to active work on the Wall next year (at Birdoswald), and who is my authority on many points in the archæology of the Wall which his recent excavations have brought to light. Much is waiting to be done, but the adequate prosecution of the work in the future will depend entirely on how much financial help is forthcoming from those interested in historical research. I was very fortunate in falling in with the Three Days' Pilgrimage of the Society of Antiquaries of Newcastle-upon-Tyne and the Cumberland and Westmorland Archæological Society, and in being allowed to join it, in September 1920; and I have to thank the members for their kind welcome to a stranger, and for their readiness to help me. In this connection I must specially mention Mrs. T. H. Hodgson, Mr. Robert Blair, F.S.A., and Mr. W. G. Collingwood, F.S.A. _Archæologia Æliana_, issued yearly by the Society of Antiquaries of Newcastle-upon-Tyne, and the annual _Transactions_ of the Cumberland and Westmorland Antiquarian and Archæological Society have been of the greatest service as works of reference. To the former I am also indebted for the plans of the Roman Bridge and of Cilurnum and Borcovicium (Figs. 6, 8, and 12). From the work entitled _Romano-British Buildings and Earthworks_, by the late Mr. John Ward, {xvii} F.S.A., the author and the publishers (Messrs. Methuen & Co.) have kindly allowed me to take Figs. 9, 10, 11, 12, and 14. Readers who wish to study the latest discoveries with regard to the Vallum will find them in the recently published _The Purpose and Date of the Vallum and its Crossings_, by Mr. F. Gerald Simpson and Dr. R. C. Shaw (Titus Wilson, Kendal). It forms part of vol. xxii. of the Transactions of the Cumberland and Westmorland Antiquarian and Archæological Society, but it can also be obtained separately. For those who do not care to walk all the way, and who wish to see a great deal of the Wall in a short time, the George Inn at Chollerford makes a delightful centre. It stands on the bank of the North Tyne, with well-kept gardens sloping down to the water's edge, just where a five-arched stone bridge crosses the river. The bridge dates from 1771, the year when every bridge over the Tyne except the one at Corbridge was swept away by heavy floods.