Can anyone tell me? I see many similarities between Welsh and Greek
(Thinking particularly of dduw / theo, but other examples as well)
Was the Welsh language influenced by missionaries making extensive use of Greek scriptures?

They just arise from the fact that Welsh and Greek ultimately stem from the same roots (have a look at this).

A lot of theological words in Welsh probably come via the latin.  The Welsh word for church is eglwys (think I've spelled that right), which has fairly obvious connections with the equivalent in romance languages, eglise in French and iglesia in Spanish.

Almost certainly because it came via the Germanic form used by the Saxons, pw. If you consider that Christianity was widespread here long before the Norman invasion, then the likelihood of another word from a different root replacing it in the common tongue would be rather small.

I've looked it up on the online OED, and I've never seen a word with such a complicated etymology.

Some samples:

 The ulterior derivation has been keenly disputed. The L. circus, and a Gothic word kêlikn ‘tower, upper chamber’ (app. originally Gaulish) have both been proposed (the latter suggested by the Alemannic chîlihha), but are set aside as untenable; and there is now a general agreement among scholars in referring it to the Greek word {kappa}{gumac}{rho}{iota}{alpha}{kappa}{goacu}{nu}, properly adj. ‘of the Lord, dominicum, dominical’ (f. {kappa}{gumacacu}{rho}{iota}{omicron}{fsigma} lord), which occurs, from the 3rd century at least, used substantively (sc. {delta}{gwfrown}{mu}{alpha}, or the like) = ‘house of the Lord’, as a name of the Christian house of worship.

The chief objections to this derivation of the Teutonic (and Slavonic) name are the following. The ordinary name for ‘church’ in Gr. was {elenis}{kappa}{kappa}{lambda}{eta}{sigma}{giacu}{alpha}, and this (or {beta}{alpha}{sigma}{iota}{lambda}{iota}{kappa}{ghacu}, BASILICA) was the name which passed into Latin and all the Romanic langs.; also, into all the Celtic langs., OIr. eclais, Ir. and Gael. eglais, Manx agglish, OWelsh ecluis, W. eglwys, Cornish eglos, -es, -is, Breton iliz. Hence, an à priori unlikelihood that any other Greek name should have passed into the Teutonic languages. Moreover, {elenis}{kappa}{kappa}{lambda}{eta}{sigma}{giacu}{alpha} was actually adopted in Gothic, where as aikklêsjô it occurs in the N.T. many times. But as the sense here is not that of the place of public worship, but of the Christian society or assembly, it forms no evidence against the coexistence of a Gothic repr. of {kappa}{upsilon}{rho}{iota}{alpha}{kappa}{goacu}{nu}, in the sense of the‘Lord's house’.

Cf. also the Slavonic forms: OSlav. cr{ibreve}ky, 10th c., cr{ubreve}ky fem., later cr{ubreve}k{ubreve}ve, c{imac}rkov{ibreve}, Russ. cerkov', Bulg. {chacek}erkova, Serbian crkva, Slovenish cerkev, Chekh cirkev (obs.), Pol. cerkiew (but only for ‘Greek church’), Lusat. cyrkej.

Anglo-Saxon has cirice, where both c's are softened*: by Chaucer's time the middle syllable had disappeared: he says of the Wife of Bath: "Husbondes at chirche dore she hadde five", so (problems with the root notwithstanding) the word can be traced unbroken through the English language for at least one thousand two hundred years. The Scots version, kirk is the same root in a Scandinavian version.

[* i.e. aspirated: I was in Italian mode there, it seems.]

Thank you for that post Don Basilio.  We seem to be getting off Churches & Cathedrals but it is fascinating.

Rhygyfarch, who wrote the Life of Saint David in the eleventh century, speaks of a Synod which was held in Llanddewi Brefi, Ceredigion, sometime around the year 569. This was twenty-eight years before Saint Augustine landed in Kent in 589, on the orders of the Pope, to Christianise Britain. Augustine’s task was to evangelise the pagan Anglo-Saxons, who had flocked into south-east England following the departure of the Romans. The Welsh Christian tradition was already old by his time, and the Latin language had left its mark on it (the Welsh words eglwys, mynach, pechod from the Latin ecclesia, monachus, peccatum).

The Welsh word Pasg comes from the Latin Pascha (from the Hebrew Pesach). The English words are Lent and Easter – Lent from Old English lencten (‘lengthen’ – a reference to the days lengthening in spring), and Easter from the name of the pagan goddess, Eostr. The Welsh language and British Christianity share the same cradle. The newcomers to this island were Christianised much later.

Although the Church in Wales is Yr Eglwys yng Nghymru you don't find many Churches referred to as Eglwys.  The fifth and sixth centuries were the age of the Welsh saints, the founders of the llannau. The word llan originally meant ‘a plot of land’, and then ‘a plot of land on which a church had been built’, and then the ‘church’ itself. A great number of place-names in Wales include the element llan, followed by the name of the saint who founded it, i.e. Llanilltud or Llanddewi or Llanvihangel (St. Michael)



Much food for thought on this thread.

Yes, I'm intrigued, but Die Wies and Vierzehnheilgen have a lightness not in evidence here.

Thank you for posting the pikkies, though.

There was a baroque statue of St John Nepomuk on the bridge at Wurzburg - he is supposed to have been thrown into the river at Prague for refusing to reveal the secrets the queen had revealed to him in confession.