Of the original fords we have already drawn up a list. Few have, merely as fords, proved to be of strategic or commercial value. Oxford may have been an early exception; and the difficult passage at Abingdon founded a great monastery but no military post: the rise of each was connected, as was Reading (which had no ford), with the junction of a tributary. Wallingford alone, in its character of the last easy and practicable ford down the river, had for centuries an importance certainly due to geographical causes alone. Two principal events of English history--the crossing of the Thames by the Conqueror and the successful challenge of Henry II. to Stephen--depend upon the site of this crossing. Long before their time it had been of capital importance to the Saxon kings, so early as Offa and so late as Alfred. If the bridges built at Abingdon in the fifteenth century had not gradually deflected the western road, Wallingford might still count the fourteen churches and the large population which it possessed for so many centuries. Apart from Wallingford, however, the fords, as fords, did little to build up towns or to determine the topography of English history. Of more importance were the crossings of the great _roads_. When one remembers that the south of England was originally by far the wealthiest part of the country, and when one considers the shape of Ireland, it is evident that certain main tracks would lead from north to south, and that most or all of these would be compelled to cross the Thames Valley. We find four such primeval ways. One from the Straits of Dover in the south-east to the north-western centres of the Welsh Marches and of Chester, the Port for Ireland, and so up west of the Pennines. This came in Saxon times to be called the _Watling Street_, a name common to other lesser lanes. Another, the converse to this, proceeded from the metal mines of the south-west to the north-east until it struck and merged into other roads running north and east of the Pennines. This came to be called (as did other lesser roads) the _Fosse Way_. A third went more sharply west from the southern districts, and connected them not with the Dee, but with the lower Severn. This track ran from the open highlands of Hampshire through Newbury and the Berkshire Hills to Gloucester, and was called (like other lesser tracks) the _Ermine Street_. Finally, a fourth went in a great bend from these same highlands up eastward to the coast of the North Sea in East Anglia. This was called in Saxon times the _Icknield Way_. All these can be traced in their general direction throughout and for most of their length minutely. All were forced to cross the Thames Valley, which so nearly divided the whole of South England from east to west. Of these four crossings the first in point of interest is that which the _Ermine Street_ makes over the upper Thames at _Cricklade_.