Attested:  (1) Ptolemy 2,3,4 Τρισαντωνος river mouth
  (2)  Possibly Tacitus Annals 12,31 castris antonam emended to cis trisantonam

Where:  (1) The river formerly called Tarrant, but now Arun, in Sussex, which reaches the sea by Littlehampton, at TQ027011.
(2)  The river Trent, variously spelled Treenta, Treanta, Treontan etc by Bede in AD 731

Notes:  Ekwall (1928:415-8) set out the argument that an original British *Trisantōn suffered the Celtic conversion of S to H, then lost the H, and gave rise to a series of rivers called Trent, Tarrant, etc around Britain and the Continent.  R&S pp 476-8 reprised that analysis and partially highlighted three questions: whether to segment the name Tris-antona or Tri-santona; whether the beginning could be Celtic for ‘very’ or ‘trans’; and whether the end could come from PIE *sent- ‘to go’ or from *anton ‘river.  Coles (1994) thought that the name Trisantona arose from these rivers’ ancient importance as transport routes.  All this is very plausible, but it also has huge problems.  The whole concept of specifically Celtic etymologies, as distinct from pan-European or Roman ones, has largely collapsed.  Names like Trent might be related (etymologically or by later confusion) to torrent, derived from Latin torrens, and possibly referring to tidal bores.  That emendation to Tacitus is highly debatable.  Above all, initial Tris- cries out to be interpreted as ‘three, triple’.  The Sussex Arun is formed by the convergence of three main rivers at its former limit of navigation (and Roman crossroads) near Pulborough: the Rother, the Stor, and the upper Arun.  Exactly how it reached the sea in Roman times is uncertain, but the flood-risk map for that area shows two more drainage routes to the sea through the Bognor-Littlehampton conurbation, and two side-streams converging on a point that might have been the head of an ancient estuary.  Three possible ways to explain why Trisantona was a triple!  Much the same holds for the river Trent, whose tributaries of course form a fractal pattern but there is a definite threefold merging of the major rivers Derwent, Soar, and upper Trent roughly where the modern M1 crosses the Trent.  If there is merit in this Tris=triple analysis, the *antona part would make sense as ‘opposite water, tributary’ by the logic spelled out under Aventio where *antia might be similar to Greek αντιος ‘opposite’.

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Last Edited: 5 September 2016