According to my research, the confessional screen was implemented to
increase the anonymity of the penitent, and to separate priests from
Because you recall reading or hearing that they were put in place
because of alleged priest assault, I searched for the history "A Tour
of a Catholic Church" by Thomas Richstatter, O.F.M., S.T.D.
"In some churches it is common to see one or more confessionals, small
"rooms" built out from the side or back wall of the church containing
a place for the priest confessor to sit, separated by a screen or
grill from the place for the penitent to kneel and confess his or her
sins. Confessionals appeared in Catholic churches during the 16th
century and were common until just recently. The current ritual for
the individual celebration of the sacrament offers the penitent a
choice between speaking face-to-face with the priest or the anonymity
provided by the confessional screen. This option has necessitated the
remodeling of confessionals in some churches and the construction of a
reconciliation chapel in others."
I found nothing associated with molestation or assault there but then
I found this reference:
"Several types of confessional were in existence during the Middle
Ages. In the 12th century the priest was seated while the penitent
knelt in front of him. From the 14th century in Sweden, where men
lived alongside women in double monasteries, grilles were inserted in
special recesses in the choir walls to prevent the priest from coming
into contact with the sisters."
(Please read the full article to see further confessional developments.)
The coed monasteries situation came the closest to possibly being
associated with some type of molestation or uninvited advances from
priests toward sisters.
However, further research turned up this:
" The seduction of female penitents by their confessors,
euphemistically known as solicitatio ad turpia or "solicitation," has
been a perennial source of trouble to the Church since the
introduction of confession, more especially after the Lateran Council
of 1216 rendered yearly confession to the parish priest obligatory. It
was admitted to be a prevailing vice, and canonists sought some
abatement of the evil by arguing that the priest notoriously addicted
to it lost his jurisdiction over his female parishioners, who were
thus at liberty to seek the sacrament of penitence from others. (1) A
Spanish authority, however, holds that this requires the licence of
the parish priest himself and, when he refuses it, the woman must
confess to him, after prayer to God for strength to resist his
"It was an evil of which repression was impossible, notwithstanding
penalties freely threatened. A virtue of uncommon robustness was
required to resist the temptations arising from the confidences of the
confessional, and so well was this understood that an exception was
made to the rule requiring perfect confession, for reticence as to
carnal sins was counselled, when the reputation of the priest rendered
it advisable. (3) Few women thus approached, whether yielding or not,
could be expected to denounce their pastors to the bishop or provisor,
and for her who yielded the path to sin was made easy through the
universal abuse of absolution by her accomplice, and this, although
objected to on ethical grounds, was admitted to be valid."
From A History of the Inquisition of Spain, Volume 2, by Henry Charles Lea
This last reference seems to bear out your memory on the topic.
The material goes on state "Few women thus approached, whether
yielding or not, could be expected to denounce their pastors to the
bishop or provisor, and for her who yielded the path to sin was made
easy through the universal abuse of absolution by her accomplice, and
this, although objected to on ethical grounds, was admitted to be
valid. (4)On the other hand, the peccant confessor could rely on
obtaining absolution from a sympathizing colleague, at the cost of
penance which had become habitually trivial.
"The intercourse between priest and penitent was especially 
dangerous because there had not yet been invented the device of the
confessional--a box or stall in which the confessor sits with his ear
at a grille, through which the tale of sins conceived or committed is
whispered. Seated by his side or kneeling at his feet, there was
greater risk of inflaming passion and much more opportunity for
provocative advances. It was not until the middle of the sixteenth
century that the confessional was devised, doubtless in consequence of
the attacks of heretics, who found in these scandals a fertile subject
of animadversion. The earliest allusion to it that I have met occurs
in a memorial from Siliceo of Toledo to Charles V, in 1547. (5) In
1565 a Council of Valencia prescribed its use and contemporaneously S.
Carlo Borromeo introduced it in his Milanese province, while in 1614
the Roman Ritual commanded its employment in all churches. 6) "
The entire chapter is fascinating. I recommend you read it all, and
thank you for asking such an interesting question!
confessional history Catholic
confessional Catholic "history of confession"
"history of confessional"
"history of the confessional"
"confessional screen" history
"confessional screen" origin
"Carlo Borromeo" confessional [a.k.a. Charles Borromeo]
"Charles Borromeo" confessional
confessional grille monasteries