From: Piotr Gasiorowski
Message: 4443
Date: 2000-10-18

Michal asked about Polish rivernames.
Southern Poland shares many hydronyms with Illyria, Pannonia and the NW Balkans, e.g.:
    Sawa  ~ Sava/Sau (ancient Savus/Sauos).
    Raba  ~ Rába/Raab (Arabo:n).
    Mroga ~ Cz./G. Morava/March (Marus < Germanic Maraha < *Margos)
          ~ Serb. Morava (Margos).
The southern rivernames cannot be Slavic imports -- many of them are attested in ancient sources.
Western and northern Polish hydronyms often resemble those found in northern Italy or along the Baltic-Adriatic route, e.g.:
    Notec' (13c. Notes') ~ Venetic Natiso/Natissa
           < *nat-is- (near Aquileia),
           cf. Latin nato: 'float, flow'.
    Wierzyca (12c. Verissa) < *xwer- + -is-
           cf. Verona, Venetic Varamus (river),
           German Wörsbach, Werse.
    Uiaduas (the Oder in Ptolemy) < *wi-adu-a-s
           ~ Venetic Aduas < *adu- 'watercourse'.
Outside Poland, the Elbe/Labe < *albH- 'white' can be suspected of having Italic connections
Some names have cognates in both Illyrian and Venetian areas:
    S'rem (town on the River Warta, no Slavic etymology) 
           ~ Illyrian Sirmium (modern Srijem), Sarminium,
           N Italian Sermione (village), Sermenza (river),
           cf. Thracian Sermios (river) < *ser-m-(j)o-
           from *ser- 'flow'.
Still other names may be too old to be assigned to a particular branch:
    Drwe,ca < *Dru-ont-ja: from *dreu- 'run' (also with *-nt-)
           one of the most widespread IE rivernames,
           with cognates from the British Isles to India,
           also in Italy (Truentus, a river in Picenum), but
           *dreu- is unattested in Germanic and Balto-Slavic
           (except in rivernames, e.g. Drawa ~ Drava/Drau).
    Bzura < Brzura < *brju-r-a < *bHreu(h)-r/n-,
           cf. Greek phrear, -atos 'well', English burn < brunna
Such examples could be multiplied.