The two weeks between Passion Sunday and Easter. The last
week is Holy Week, while the first is called by the Latins
“Hebdomas Passionis”, by the Greeks “Week of the palms”
(from the Sunday following). During this time the monks of
the East, who had chosen the desert for a severer mode of
life, returned to their monasteries. The rubrical prescriptions
of the Roman Missal, Breviary, and “Caeremoniale
Episcoporum” for this time are: before Vespers of Saturday
preceding Passion Sunday the crosses, statues, and pictures of
Our Lord and of the saints on the altar and throughout the
church, with the sole exception of the crosses and pictures of
the Way of the Cross, are to be covered with a violet veil, not
translucent, nor in any way ornamented. The crosses remain
covered until after the solemn denudation of the principal
crucifix on Good Friday. The statues and pictures retain their
covering, no matter what feast may occur, until the Gloria in
Excelsis of Holy Saturday. According to an answer of the S.
R. C. of 14 May, 1878, the practice may be tolerated of
keeping the statue of St. Joseph, if outside the sanctuary,
uncovered during the month of March, which is dedicated to
his honour, even during Passiontide. In the Masses de
tempore the Psalm Judica is not said; the Gloria Patri is
omitted at the Asperges, the Introit, and the Lavabo; only two
orations are recited and the Preface is of the Holy Cross. In
the Dominical and ferial offices of the Breviary the doxology
is omitted in the Invitatorium and in the responses, whether
long or short. The crosses are veiled because Christ during
this time no longer walked openly among the people, but hid
himself. Hence in the papal chapel the veiling formerly took
place at the words of the Gospel: “Jesus autem abscondebat
se.” Another reason is added by Durandus, namely that
Christ’s divinity was hidden when he arrived at the time of
His suffering and death. The images of the saints also are
covered because it would seem improper for the servants to
appear when the Master himself is hidden. Newadvent.org