Thanet, the best known and most important island, was in the 5th century separated from the mainland by the Wantsum and the estuary of the Stour, which gave an expanse of water mainly two miles broad, so that vessels from or to London sailed from Reculver to Richborough, and avoided the longer and rougher route round the North Foreland. To guard this sea-way the Romans had placed their forts of Regulbium (Reculver) and Rutupia (Richborough) at its northern and eastern entrance. Now, and for long, by the dwindling of the Stour and the practical extinction of the Wantsum, Thanet is but in name an island. Even writing in 1570, Lambarde calls it a peninsula. It is said that its Celtic name was Rimn—a headland, and that its later Saxon name, Tenet, means a beacon. Solinus, who wrote about A.D. 80, calls it Ad-Tanatos (Thanatos, Greek for Death, because its soil killed snakes even when exported for that purpose!). Nennius, in the 8th century, says Guorthigern handed to Hengist and Horsa the island, “which in their language is called Tenet, but in British speech Ruoihm,” or Ru-oichim. In a charter of 679 it appears as Tenid. The name, says McClure, may involve the Celtic Tann for oaks, as in Glastenec, an early form of Glastonbury, surviving in the English, Tanner, Tanyard, etc. From this root is derived the Breton place-name Tannouet. Tenid is its oldest Saxon form, and the _Saxon Chronicle_ records that in 969 Eadgar ordered Tenetland to be pillaged. Variations in the Spelling of Place-Names. In the search for the meaning of a place-name it is necessary to go back as far as possible and discover, if we can, its earliest form. The _Anglo Saxon Chronicle_, and the later Domesday Book of 1086; the gradual blending of Saxon and Norman into the English tongue; and then the invention of printing; all may have had an effect on the pronunciation, and so the spelling, of a word. Also there is the tendency to shorten a long word, as when Pepingeberia becomes Pembury, or Godwinston, through Gusseton, becomes Guston. And before the standardization of spelling which printing to a great extent effected, and in written documents such as charters or wills, the most remarkable variations will occur according to personal varieties of pronunciation. Even now, though every one reads “I am going,” in one county you may hear “I’m a gowin’,” in another “I be gooin’,” in another “I be gwaine,” and so forth, and so one wonders less at the various forms in which a name appears in writing in Saxon, in Norman, or in Early English days. As a general rule the earliest form will be best and most likely to indicate why a name was given. To illustrate this source, both of information and of error, let me take two Kentish place-names—Westenhanger and Tenterden—giving the dates at which I find the various forms.