The prayer most people can say without thinking, which is the point of it. Half is two greetings straight out of the Gospel of Luke; the other half was added much later and asks for exactly one thing.
Two greetings, and then one request. The greetings are not ours — an angel said the first and a pregnant woman the second, and the prayer simply repeats them to her. The name Jesus at the end of the first half was put in during the thirteenth century so it was clear whose fruit was meant.
Then the half that was written for us: pray for us sinners, now and at the hour of our death. It does not ask her to fix anything. It asks her to ask, and it names the two moments that matter — this one, and the last one.
Two stages, and the dates are honest. The first half is Luke 1:28 and 1:42 joined together, and it was being said as a short prayer — an antiphon — by around 1050; the joining is old and nobody's name is on it. The word Jesus was added in the 1260s, on the instruction of Urban IV.
The second half, Holy Mary, Mother of God, pray for us sinners, now and at the hour of our death, turns up in the fifteenth century in more than one form, and was fixed in the words we say by the Breviary of Pius V in 1568. So the prayer as you know it is about four and a half centuries old in its final shape, and about a thousand in its first half.
The Rosary is fifty-three of them. The Angelus is three, at six, noon and six. It is the prayer of the Daily Prayer beads on this site, five at a time so a decade is there to grow into.
And it is the most-set text in Western music after the Mass itself. Schubert's Ave Maria and Gounod's are this prayer, in Latin, and people who have never said it have wept at it.