One of the most widely used hymns in the Church, Veni, Creator Spiritus, is attributed to Rabanus Maurus (776-856). It is used at Vespers, Pentecost, Dedication of a Church, Confirmation, and Holy Orders and whenever the Holy Spirit is solemnly invoked. 

Latin
VENI, Creator Spiritus,
mentes tuorum visita,
imple superna gratia
quae tu creasti pectora. 

Qui diceris Paraclitus,
altissimi donum Dei,
fons vivus, ignis, caritas,
et spiritalis unctio. 

Tu, septiformis munere,
digitus paternae dexterae,
Tu rite promissum Patris,
sermone ditans guttura. 

Accende lumen sensibus:
infunde amorem cordibus:
infirma nostri corporis
virtute firmans perpeti.

Hostem repellas longius,
pacemque dones protinus:
ductore sic te praevio
vitemus omne noxium. 

Per te sciamus da Patrem,
noscamus atque Filium;
Teque utriusque Spiritum
credamus omni tempore. 

Deo Patri sit gloria,
et Filio, qui a mortuis
surrexit, ac Paraclito,
in saeculorum saecula.
Amen. 


English

COME, Holy Spirit, Creator blest,
and in our souls take up Thy rest;
come with Thy grace and heavenly aid
to fill the hearts which Thou hast made.

O comforter, to Thee we cry,
O heavenly gift of God Most High,
O fount of life and fire of love,
and sweet anointing from above.

Thou in Thy sevenfold gifts are known;
Thou, finger of God's hand we own;
Thou, promise of the Father, Thou
Who dost the tongue with power imbue.

Kindle our sense from above,
and make our hearts o'erflow with love;
with patience firm and virtue high
the weakness of our flesh supply.

Far from us drive the foe we dread,
and grant us Thy peace instead;
so shall we not, with Thee for guide,
turn from the path of life aside.

Oh, may Thy grace on us bestow
the Father and the Son to know;
and Thee, through endless times confessed,
of both the eternal Spirit blest.

Now to the Father and the Son,
Who rose from death, be glory given,
with Thou, O Holy Comforter,
henceforth by all in earth and heaven.
Amen.