Maurus predates the charasmatic movement by several centuries, being born in the German city of Mainz in about 776. A great scholar, he became a head-master (he was given the title 'Teacher of Germany') and later the abbot of the Benedictine monastery of Fulda. Under his stewardship the abbey flourished, and eventually he was made Archbishop of Mainz (845), one of the most influential European sees. As well as for scholarship, Maurus was also known for his generosity to the poor. Apart from his hymnody, he was a well known theological writer and most interestingly also found the time to write De rerum naturis, also known as De universo. This is a fascinating encylopaedia (in relatively simple Latin) with entires on such diverse topics as 'God', 'Fish', 'Mountains', 'Gold', 'Marriage', 'Pagans' and 'Public Buildings'. He died near Mainz in 856.
As well as being sung as part of the office at this time of year, the Veni Creator forms part of the ritual for ordination ceremonies and may fittingly be used at any time when the invocation of the Holy Spirit is particularly appropriate. According to the 1968 Enchiridion of Indulgences a partial indulgence attaches to the Veni Creator, with a plenary indulgence for public recitation on Pentecost or New Year's Day.
According to the Catholic Encylopedia there used to be an alternative doxology at the end of the hymn which was suppressed in 1899. Curiously, the current Editio Typica of the Breviary does not include either doxology, presumably because the penultimate verse of the hymn is sufficently Trinitarian:
Per te sciamus da Patrem,
noscamus atque Filium;
Te utriusque Spiritum
credamus omni tempore.
However, anyone who has ever seen Poulenc's opera Dialogues des Carmélites will keenly miss the traditional doxology which is chillingly sung by Blanche de la Force as she suffers martyrdom at the guillotine.
Deo Patri sit gloria,
et Filio, qui a mortuis
surrexit, ac Paraclito,
in saeculorum saecula.