Hi there
as this site is the only one i found containing the word waleness as reference to being a Welsh from wales
https://groups.google.com/forum/#!topic/rec.sport.rugby.unio...
So i propose this as a rendering for the archaic term at hand ِشخصية أو شىء قديم من مقاطعة ويلز
Hopefully that would be helpful
GL


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Note added at 5 hrs (2013-10-05 08:56:33 GMT)
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here is agreat source for welsh language though i didnot find any thing about our term http://www.lexilogos.com/english/welsh_dictionary.htm
you should charge them additional rate for this term :)