There are three methods available for determining the age of artefacts such as those from Ferriby: dating by comparison or association with other objects or deposits of known age; direct dating by radio-carbon determination; and absolute dating by dendrochronology. The first of these, as has already been emphasized, cannot be relied upon fully owing to the ever-present possibility that objects found in a water-laid deposit could have been sorted or otherwise shifted horizontally or vertically before discovery. The second remains imprecise owing to the considerable range of variation inherent in the process and, in the Ferriby case, the still relatively small (albeit growing) number of determinations at present available. Only the third gives promise of complete reliability and here again the quantity of evidence is low, the quality is less than perfect where timber had deteriorated before examination and, in particular at the time of writing, the long awaited curves taking the table of measured growth rings for northeastern England back into the the second millennium Be have not yet been linked together. Connections may be made within a few years but, until they are, comparisons are alone possible with floating chronologies whose absolute age can be estimated only within broad limits. Evidence for the age of artefacts and that for reconstruction of the ancient environment are interrelated and consideration of the latter is undertaken first to demonstrate the geological, topographical,
and climatic background for the periods before, during, and after the deposition of the boats at the site. Discussion of the dating evidence follows and this leads on to examination of the relevant archaeological framework for the period during which the design of such boats evolved and the fully developed examples which we have were in use.