43 And having fulfilled the days, when they returned, the child Jesus remained in Jerusalem; and his parents knew it not. consummatisque diebus, cum redirent, remansit puer Jesus in Jerusalem, et non cognoverunt parentes ejus.  44 And thinking that he was in the company, they came a day's journey, and sought him among their kinsfolks and acquaintance. Existimantes autem illum esse in comitatu, venerunt iter diei, et requirebant eum inter cognatos et notos.  45 And not finding him, they returned into Jerusalem, seeking him. Et non invenientes, regressi sunt in Jerusalem, requirentes eum.  46 And it came to pass, that, after three days, they found him in the temple, sitting in the midst of the doctors, hearing them, and asking them questions. Et factum est, post triduum invenerunt illum in templo sedentem in medio doctorum, audientem illos, et interrogantem eos.  47 And all that heard him were astonished at his wisdom and his answers. Stupebant autem omnes qui eum audiebant, super prudentia et responsis ejus.  48 And seeing him, they wondered. And his mother said to him: Son, why hast thou done so to us? behold thy father and I have sought thee sorrowing. Et videntes admirati sunt. Et dixit mater ejus ad illum : Fili, quid fecisti nobis sic? ecce pater tuus et ego dolentes quaerebamus te.  49 And he said to them: How is it that you sought me? did you not know, that I must be about my father's business? Et ait ad illos : Quid est quod me quaerebatis? nesciebatis quia in his quae Patris mei sunt, oportet me esse?  50 And they understood not the word that he spoke unto them. Et ipsi non intellexerunt verbum quod locutus est ad eos.  51 And he went down with them, and came to Nazareth, and was subject to them. And his mother kept all these words in her heart. Et descendit cum eis, et venit Nazareth : et erat subditus illis. Et mater ejus conservabat omnia verba haec in corde suo. To commemorate in the liturgy the fifteenth centenary of the Council of Ephesus (held in A.D. 431), which vindicated the title of Theotokos or "Mother of God" for our Lady, Pope Pius the XI in the year 1931 instituted this feast to be observed by the whole Church.