The connection of 'agios with the Sanskrit becomes more apparent if you know that in modern demotic Greek the word is pronounced "hayyos" (the gamma being soft, instead of hard as in ancient and Koine Greek). Hence, the name of the great church of Byzantium, now a mosque, 'Agia Sophia, is generally pronounced now as Hayya Sofia. The Greek church in East Baltimore, 'Agios Nikolaos, (St. Nicholas) is Hayyos Neekolouse.

There is a parallel softening of the letter 'g' in Old English, where it is often pronounced something like our 'y'. For instance, the OE "He segde" (he said) is pronounced "hay say-de"; hence the spelling became "sayde", "saide", "said" in succesive ages.