C 68 ] 
When this inundation happen’d, it is perhaps in 
vain to inquire ; but two pieces of hiftory occur to 
me, which poffibly may lead us near the time. In 
the time of Strabo and Diodorus Siculus, their com- 
merce feems to have been in full vigour ; “ Abun- 
" dance of tin carried in carts,’’ fays Diodorus Sicu- 
lus : — “ But ten iflands in all, (fays Strabo) and 
“ nine of thole inhabited.” The deftrudtion there- 
fore of Sylley mull be plac'd after the time of thefe 
authors ; that is, after the Auguftan age: but at what 
time after, I find nothing as yet can determine. 
Plutarch indeed (of the Cejj'ation of Oracles') hints, 
that the iflands round Britain were generally unpeopled 
in his time. If he includes Sylley among them, then 
this defolation mud have happened between the reign 
of Trajan, and that of Auguflus. However that be, 
Sylley, tho’ not intirely deftitute of inhabitants, feems 
to have been noted for two or three banifhments du- 
ring the empire of the Romans in Britain. 
It continued negledted, till trade began to thrive, 
flipping- increafe, and naval wars to be carried on in 
this weftern world. Then its commodious fituation 
at the opening into both the chanels foon fhew’d of 
what importance it was for Britain to poflefs it, and 
how dangerous it might be to the fafety and trade of 
Britain, if in an enemy's hand. 
This feems to be the reafon, why Athelflan made 
a voyage to, and conquer’d, thefe iflands. That 
prince was taught by his grandfather Alfred's wife 
maxims, that the proper and natural fecurity of Bri- 
tain lay in the royal navy, and its riches in trafiick - y 
and he law, that neither of them could be well pro- 
vided 
