In the ancient Christian days Mass would begin with a litany, a series of petitions to God, to which the people would respond "Domine, miserere nobis," or "Lord, have mercy on us." This tradition of litanies during the liturgy continues in the Byzantine rite today, whereas it is primarily something done in processions or at ordinations in the Roman rite now. By the pontificate of St. Gregory the Great, who ascended to the Petrine chair in 590 A.D., the litanies had vanished but the response, "Lord, have mercy," remained. St. Gregory, believing the Roman rite should still retain Greek vestiges, changed the response from Latin to Greek ("Kyrie, eleison"). Rather than just a series of exclamations, the "Kyrie" became a series of three invocations, each invocation composed of three petitions. The first three directed to God the Father (Kyrie eleison), the second three to God the Son (Christe eleison), and the last three to God the Holy Ghost (Kyrie eleison).
This remained the tradition in Rome until 1969, but not through all of Europe. The great cathedrals of Spain, Gaul—particularly Rouen, and England—especially Salisbury—began to trope or "farce" the Kyrie's with Latin exclamations and titles of the Persons to Whom they are addressed. I have found one such version which I believe to be of Gaul, given its musical style of "organum," a droning background noise which resembles ancient Byzantine chant whilst a cantor sings the main petition aloud. This style is somewhat like a primitive polyphony in style and was likely brought to the West through the Crusades. This text version is from the 12th or 13th century and most religious and political enthusiasm for the Crusades derived in France, which is my logic for sourcing this rendition from there.