The position of the various fortresses shows that it was not necessary, according to the Roman plan of defence, that one fort should command views of its neighbours. Reculver and Richborough, Richborough and Dover, Dover and Lymne, Lymne and Pevensey, were in no case visible from each other, although the distance which separated them was not great in every case. Under these circumstances it is not remarkable to find evidences, as will presently be explained, of special provision for signalling between the fortresses. THE COUNT OF THE SAXON SHORE During the early part of the Roman occupation of Britain the chief mode of defence adopted against piratical incursions was the navy, _classis Britannica_. This, for the most part, moved in those waters which lay between the British and Gaulish coasts, answering to what we now know as the Straits of Dover and the southern part of the North Sea. For a time the navy was able to keep the seas free from pirates, but towards the end of the third century the trouble became greater than ever. Raiders came in large numbers both to our own coasts and also to the Continental coasts opposite, to both of which the name of the Saxon Shore was given. The Romans decided to take strong measures to put an end to the trouble. For this purpose they appointed a special officer, one Marcus Aurelius Valerius Carausius, commonly known by his last name. The appearance of Carausius on the stage of history brings into prominence a man of strong but unscrupulous character. He is believed to have allowed the pirates to carry on their work of plunder at their pleasure, and then, having waited for the proper moment, he relieved them of their booty on the return journey. In this way he acquired great riches, and in due course he employed the fleet, not against the enemy of Rome, but against Rome, and in such a way as to render Britain independent. After several ineffectual attempts to break his power, Diocletian and Maximianus found it necessary to recognize him as their colleague in the empire, a triumph which Carausius commemorated by striking a medal bearing as a device three busts with appropriate emblems the legend: (_ob._) CARAVSIVS . ET . FRATRES . SVI (_rev._) PAX AVGGG. Carausius was murdered by his chief official, Allectus, in the year 293. Shortly after his death, and when the British province had ceased to be independent of Rome, an official was appointed called the Count of the Saxon Shore.