The laws of Athelstane provide that "all marketing be within the port (town) and witnessed by the Portreve or other unlying man." That is in "open market." [Illustration: FIG. 29.--COIN OF ALFRED WITH MONOGRAM OF LONDON. ENLARGED.] From the moment when we first hear of it London has been a famous port and market. Tacitus speaks of it as "celebrated for the resort of merchants with their stores." "London," says Beda, speaking of the opening of the seventh century, "was a mart town of many nations which repaired hither by sea and land." In Athelstane's appointment of moneyers to the realm London was assigned eight, this being two more than any other place. The coins of Alfred struck in the city form a large series. The monogram of London which fills the reverse of some of them is a quite perfect design,[173] and it deserves to be better known and largely used (Fig. 29). As to the relation of Saxon and Roman London a few words may be said. Wren held that the Roman Forum was at London Stone, while Stukeley suggested the Stock's Market on the site of the present Exchange. Excavations at Chesters and Silchester have shown that the forum in each case occupied a large "insula" right in the centre of the city, and this would agree best with Stukeley's site.[174] It is possible that it may have extended along by the east bank of the Walbrook as far as Cannon Street. The assumption of old writers, that Roman London would be symmetrically planned, with streets crossing at right angles, is not necessarily true. The streets of mediæval London in their main lines were not more irregularly laid out than the streets of Pompeii. The recently excavated city of Silchester is more regular, but this city was probably laid out once for all, whereas London was just as probably the result of gradual growth. In many respects, however, Silchester affords a close parallel to London.