Known variously as the Vespers for the Blessed Virgin, the Vespers of 1610 or just the “Monteverdi Vespers”, the 400th anniversary in 2010 resulted in a number of significant performances and new recordings, but its technical challenges serve to prevent it from becoming ubiquitous and to make it natural territory for The Sixteen. Conductor Harry Christophers describes the Vespers as “quite simply one of the greatest works of sacred music ever written” and surely few would argue with that. Much debate has ensued about the actual purpose and, sometimes, the full composition of pieces, but it is generally accepted that Monteverdi presented the collection to act as an (ultimately successful) interview portfolio for a new job as music director at St Mark’s Basilica in Venice, rather than as a coherent liturgical setting to be performed together.

Latin Vespers were the main evening devotions in the Catholic Church at the time, and Monteverdi included settings for all main items such as hymns and psalms. But he also included four “sacred concertos”, which do not form part of the Vespers and whose purpose is not entirely clear but which punctuate the lengthy piece with passionate and expressive interludes. Alternately prayerful, mystical, joyful and occasionally sensual, the work demands supreme technical ability from singers and players, but allied with real focus and commitment to achieve the required spiritual intensity.

Logistically much more of a challenge than their long-standing annual Choral Pilgrimage, this is the first programme where The Sixteen has toured with an accompanying orchestra. In effect, Christophers chose two orchestras: a relatively sparse string section but supplemented with two recorders which definitely added an extra “vocal” dimension to the strings; and secondly a brass orchestra with cornets (early wooden trumpets, fiendishly difficult to play apparently), sackbutts (early trombones) and an early version of a bassoon known as a dulcian. Pivotal to many of the individual pieces was the experienced continuo section of Baroque harp (Frances Kelly), chamber organ (Alistair Ross) and theorbo (David Miller). The size and composition of the orchestra was beautifully matched to the choir, and the sight of Joseph Crouch playing the cello standing on one leg with the instrument resting on the seat was not to be missed.

All the soloists were drawn from the choir and gave the bonus of adding a real sense of fluidity to the proceedings as well as ensuring that the solos, duets, trios etc. were fully integrated into the overall flow of the work; furthermore it allowed Christophers to stand aside during the two “Song of Songs”, having sufficient confidence in his singers and continuo simply to leave them to it. His trust was justified during the tenor/theorbo duet Nigra Sum, performed from the central aisle. Perhaps a little less ardent than is sometimes heard, Mark Dobell’s touching interpretation lent a captivating atmosphere of intimacy een in so large a space as the cathedral. Grace Davidson’s clear soprano was particularly well suited to the Pulcra es, complete with small but perfectly judged embellishment and a well-executed Monteverdi trill. Dovetailing ideally with harp and theorbo accompaniment, and with Charlotte Mobbs’ even and powerful second soprano, this was a real highlight of the first section.

The visit to Guildford was the penultimate performance of an eight-site tour around the country. For each, The Sixteen has been joined by choristers from the participating cathedrals and so the soprano line of the Sonata sopra Sancta Maria was sung, very ably, by Guildford Cathedral’s girl choristers.

Consecrated in 1961, Guildford Cathedral is a modern building with a less-than-prepossessing brick exterior, but inside is a wonderfully towering and spacious nave, flooded with light and air, and feeling a very fitting setting for the Vespers. The acoustics of the cathedral were clear and not overly resonant, but the higher vocal notes seemed to be rather attenuated and perhaps contributed to a slightly dis-engaged ambience in the early part of the performance. But from the latter part of Duo Seraphim onwards, momentum was building in the choir and by the Nisi Dominus there was a renewed commitment and energy, and a stark reminder of why this is such a crack choir, their balanced and focused sound finally drawing in the listener to the role of engrossed participant rather than mere observer. The minor acoustical drawback aside, Christophers made every other aspect of the cathedral work for him especially for the Audi coelum where Jeremy Budd sang from the raised pulpit with all the drive and purpose needed to bring the verses to life in gripping declamation. We heard the longer, more complicated, trickier and higher version of the final Magnificat and later the stunningly virtuosic cornet playing brought to a powerful conclusion a work which still resonates more than 400 years after it was written. Altogether, an absorbing and ultimately rewarding performance of this early-Baroque masterpiece.