When I arrived at Dorchester-on-Thames, Oxfordshire, in good time for the St Birinus Festival’s Saturday evening performance of the Monteverdi Vespers in Dorchester Abbey, the village was abuzz with festivalgoers already steeped in this four-day summer festival of sacred music.

Now in its fourth year, the festival combines liturgical and concert performances, with daily Lauds, Mass, Vespers and Compline as its liturgical backbone. Some of the crowds were enjoying a quick drink in the courtyard of the George Hotel between the end of Pontifical Vespers, with Gregorian chant, at 5.30pm and the start of this concert at 6.30pm.

You can’t have too much Vespers, especially when sung to the high standards inspired by the festival’s founders, conductor and composer Ryan Wigglesworth and his wife, the soprano Sophie Bevan. Carrying my cushion to the pews (a good idea to bring one), I waited for the Venetian sounds of 1610, dreamed up by Monteverdi at his most daring and experimental, to wash over me.

And they did, blissfully and addictively. This performance of the early Baroque masterpiece was electrifying from start to finish – the start being the dramatic moment when, after the opening words “Deus in adjutorium meum intende” are sung out with Italianate gusto by a soloist (Ben Bevan), the choir and period instruments erupt in full exuberance with the first of many luscious renderings of “Gloria Patri et Filio”, which punctuate this psalm-rich piece.

I felt as if I was in Venice in 1610: a dazzling city of sackbuts, cornetts and theorbo, and of tenors duetting away and echoing each other, and sopranos too, in pairs. The piece was performed with no interval, so the spell was never broken, for which I was grateful. The soloists – sopranos Daisy Bevan and Ana Beard Fernandez, tenors Dominic Bevan (the festival director) and Felix Leach, and baritones Ben Bevan and Daniel Tate – sang from two pulpits, so we could see them and bask in the delicious sounds they made from our non-raked seating, mid-nave.

I felt tears prick my eyes at the climax of the movement “Sancta Maria, ora pro nobis”, sung by a children’s choir consisting of the children of parishioners of St Birinus Catholic Church in the village and the Thame Children’s Choir. The children had been prepared for the concert by Clare Bowler-Reed, mother of four Bevan family musicians: Sophie, Daisy, Tess and Mary. Monteverdi’s plaintive theme for those words, which implore the Virgin Mary to intercede for us, is repeated again and again to a slightly different rhythm each time, interspersed with light, almost dancing notes from the orchestra. The conductor Simon Over built steadily towards the final, impassioned “ora pro nobis”, sung out with flute-like clarity by those children.

That concert was just one of 22 events at the festival, which included a Solemn Requiem Mass, a children’s workshop with replica medieval instruments, a talk by bestselling author and former nun Catherine Coldstream, a Gregorian chant workshop, and a lecture-recital on Mary Tudor and Philip of Spain with samples of music directed by Ryan Wigglesworth and his choir, the Davey Consort.

At the start of the festival, an icon of St Birinus (the saint who was sent to Dorchester-on-Thames by the Pope in the seventh century, bringing Gregorian chant with him and baptising the king of Wessex) was carried along the street from the exquisite, tiny Catholic church of St Birinus to the Abbey, just a few hundred yards away. After Pontifical Mass on Saturday, the congregation processed back to St Birinus Church with the icon, and people came in during the rest of the afternoon to pray. This coming together of the Anglican and Catholic parishes in the village was “ecumenical in the true sense,” said John Murphy, chairman of the Davey Consort: “authentic to the traditions, and generous to each other.”

Mass at St Birinus the next morning, celebrated by Fr John Osman, was on a much smaller scale in terms of numbers (one organist, Ryan Wigglesworth, and four singers, all Bevans), but no less rich in terms of polyphonic sounds, with music by Guerrero, José Gay and Bernardo Clavijo.

The culminating event of the festival – and what an unforgettable one it was! – was an organ recital by Ian Simcock on the beautiful little Aubertin organ made especially for St Birinus Church. A superb organist, through whose fingers the spirit of Bach flows, Simcock played an all-Bach programme from the third volume of the Clavierübung, almost entirely manuals only, until at the very end the pedals came in during the “St Anne” Fugue.

Simcock ordered the programme to resemble a Mass in organ music: Kyrie, Gloria, Ten Commandments, Creed, Lord’s Prayer, Baptism, Penitence, Communion and the Holy Trinity. The pieces’ never-predictable harmonies, stunningly brought out by Simcock, reminded me how astonishingly rich Bach’s organ music is, even in manuals-only form. And when the bass pedal notes did eventually sound, in the “St Anne” Fugue, to the slow, powerful tune of “O God Our Help in Ages Past”, those bass notes seemed to give us the firm foundations we needed to go back out into the real world and resume our daily lives.

(Photographs: Marco Eastwood)