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I attached the PDF of the Raccolta, 1910 edition......
 
261. The Rosary of St Dominic.
This Devotion, called also the Psalter of Mary, consists
of the continuous recitation of the Ave Maria, said 150
times (as many times as there are Psalms), divided into fifteen
decades, each beginning with a Pater noster, while at
the same time the principal mysteries of the life, death and
resurrection of our LORD are meditated on.
To gain the following indulgences beads must be used,
though in the case of several persons saying the Rosary
together it 1s sufficient if the person leading the Devotion
uses them. They must, except in the case of i, have been
blessed by a Dominican Father or other priest duly authorized.
Persons incapable of meditating may gain the indulgences
by merely saying the Rosary devoutly. Such persons should
however endeavour, in some measure, to acquire the power
of meditating.
i. Five Years and five Quarantines, for a third part, five
decades, of the Rosary (blessed beads not necessary). T.Q.
ii. 100 Days, to all who say the fifteen, or at least five
decades for every Pa/er and Ave.
iii. Plenary, to all who say five decades every day for a
year, on any one day in the year. I, II, IV.
iv. Ten Years and ten Quarantines, once a day, to all who
say five decades in company with others, either in public or
in private.
v. Plenary, on the last Sunday of every month, to all who
are in the habit of saying with others, at least three times
a week, five decades. 1, I, III, 1v.
vi. 100 Years and 100 Quarantines, once a day, to all
associates of the confraternity who devoutly carry a rosary
about with them.
260 Leo X, Br. August 20, 1516; ; ; 713; SPI
IX, Prop. Januarv 2 1848; Pe KHL Mech ye DUE
61 Sixtus IV, Bl. May 12, 1479; Benedict XIII, April 13, August 13,
1726, May 26, 1727; Pius IX, May 12, 1851, January 22, 1858; Pius X, July
31, 1906; June 12, 1907.
THE ROSARY 239
vii. Plenary, to all associates who say the Fifteen Mysteries
in the course of the natural day, for the triumph of the
Church: 5 T5 ITIH.
N.B.—The indulgences attached to beads blessed by the
Canons Regular of the Holy Cross (see No. 193) can be
gained simultaneously with the Dominican indulgences, i.e.,
while reciting the Rosary, provided the beads are blessed
with the two blessings. (Pius X, June 12, 1907.)
Note. —Indulgences vi and vii, with many others not recorded
in the Raccolta, can be gained only by members of
the Confraternity of the Holy Rosary. To enjoy the privileges
of this confraternity it is only requisite that a person’s
name be entered on the Dominican Register, and that the
beads should be blessed as above.

* In some summaries of these Indulgences, and more particularly in that reprinted in Rome in 1518, we find 150 days and a few lines after, 200 days; but in the Bull above named published at the Office of the Reverend Apostolic Chamber in 1135, we find in both places not days but years.

Amazing...If in fact this rosary was indulgenced in 1135, that's a hundred years before the Servites order was even founded.  Devotions are usually only indulgenced when they are already in common use.  We may never know how old this rosary is.  Perhaps it is because of this devotion that the Servites were founded.  Hummmm?

We do know however, that devotion to Our Mother's sorrows was the first devotion to and requested by Our Lady herself shortly after her assumption into Heaven, when she appeared to St John the Evangelist and requested it, as told to St. Elizabeth of Hungary and confirmed by St Alphonsus de Legouri.  It was at that time that Mary requested from her Son the four promises to those whose so honoured her.
As recent as the 1980's when Mother appeared in Kibeho Rawanda she specifically requested that the Seven Sorrows Rosary be prayed.