Fr Zulsdorf's usual interesting and helpful analysis of this week's collect is available over at his blog. Fr Z argues that the collect probably dates from the time of St Leo the Great (pope from 440-461).
"...There is a marvelous clausula at the end, a standard rhythmic ending much favored in classical oratory to delight the ear of listeners and add power to periodic sentences: efficáciter cónsequámúr. Say it aloud, with attention to force and length of the syllables. I also like the nice synchesis (ABAB) structure, fideliter petimus, efficaciter consequamur (adverb verb adverb verb). There is a good example of hyperbaton, the separation of linked elements, in piis Ecclesiae tuae precibus, where piis and precibus, datives, go together. Also interesting is how two imperatives bracket the central section: adesto … praesta.
All these little elements show how finely sculpted this prayer is, how different it is from the way people would have spoken in every day discourse in the streets and homes of ancient Rome and elsewhere. There may have been a shift in the ancient Roman Church from Greek to Latin for liturgical prayer, but that Latin was not the vernacular, the commonly spoken language of the day. It was highly stylized and many of the words were actually images from Scripture or terms from Stoic and Neoplatonic philosophy.
As we have explained many times, pietas, when applied to man, is "dutifulness" and when used of God is "mercy" though retaining overtones of His fidelity to His own promises. The crammed Lewis & Short Dictionary has a lengthy entry for auctor, to be brief let's call it "creator" or "cause" or "author". Auctor appears fairly often in our Roman prayers, paired up with terms such as saeculi as in "creator of the cosmos", and omnium ("of all things"), lucis ("of light"), pacis ("of peace"), salutis ("of salvation"), vitae ("of life"). Today it is with pietatis...
We find it first of all in the Vulgate of Psalm 45: "Our God is our refuge and strength: (Deus noster refugium et virtus) a helper in troubles, which have found us exceedingly." This type of invocation of God is common in the Psalms, and therefore our earliest prayers for Mass. Very ancient Roman Collects often follow the Hebrew manner of first invoking God by some characteristic and then petitioning Him in light of that title....
O God, our refuge and strength:
be present to the devout prayers of Your Church,
O author of godliness, and grant:
that, we may efficaciously attain what we faithfully seek..."
Do go read the whole piece.