I'm curious about the composition and inclusion in the shabbat shacharit of the paragraph beginning ולא נתתו (v'lo n'tato). I understand the talmudic basis for the underlying idea, and how it fits in to the tenor of the davening but I'm looking specifically for any info on who composed it, and when and why it might have first been included in the siddur -- whether it was created (or included) as a response to a particular cultural movement in the non-Jewish world or as a reaction to any other sociological event. Does it exist in any series of old, historical, printed siddurim? Does its text have a basis in anything in particular?
According to Yerach L'Moadim - footnote 27 the composer was from Arab lands. The author of the Sefer Hayovlim was the one who made this Tefila known.