This makes no grammatical sense, perhaps you were praying to the relic of a saint?
The sentence is suppose to inquire that you passed by the relics, that you went to them to see them, that you visited them. In Romanian we say "Eu am fost la..." to indicate that we had been somewhere. This sentence covers the overall cultural-religious aspect of someone who returned from the visiting relics. If asked "unde ai fost?" they would respond "Am fost la moaștele unui sfânt." if that was the case :-)
Edit: I did find the english translation "I was to..." ungrammatical, thus I modified it. Now the acceptable sentences are "I was at/went at/had been at/had been to...." thank you for your feedback!