The Proms have long been shaped by war. During the First World War, its founders, Henry Wood and Robert Newman, went against the grain of anti-German sentiment and continued to programme jewels of the central European repertoire. The festival moved to its Royal Albert Hall home in 1941 after the bombing of the Queen’s Hall in the West End. In 1968, as Soviet tanks rolled into Prague, Mstislav Rostropovich gave a legendary performance of Dvořák’s Cello Concerto, to a hostile crowd, with the Soviet State Symphony Orchestra; at the end, he held the score aloft in solidarity, making the stage both concert and political platform. Six years later he would no longer be a Soviet citizen.

An especially auspicious space, then, for Heiner Goebbels’ Songs of Wars I Have Seen from the combined forces of the London Sinfonietta and Orchestra of the Age of Enlightenment, conducted by Chloe Rooke, at a late night concert. It was followed the following weekend by Benjamin Britten’s War Requiem from Antonio Pappano and the London Symphony Orchestra, supported by the massed voices of its own choir and the BBC Symphony Chorus – the choir and orchestra that created the world premiere recording of the piece with Britten back in 1963.

There have been several rumblings of war at the BBC Proms this season. Daniel Barenboim made a cherished visit with his West-Eastern Divan Orchestra, the group he founded with Edward Said to bring together Arab and Israeli musicians, whose aims look both more desperate and vital than ever. Violinist Anne-Sophie Mutter billed her encore at that performance – the Sarabande from Bach’s D minor Partita – as a prayer for peace; the orchestral players’ names were not given in the programme, for their protection. In a less sober mood was the conclusion to Saturday morning’s recital from Jonathan Scott – Tchaikovsky’s 1812 Overture played on the Hall’s mighty organ.

Songs of Wars I Have Seen is an hour-long musical meditation on Gertrude Stein’s war diaries, which are narrated – always by the women of the ensemble, both alone and in chorus – over a cellular score by Goebbels and Matthew Locke’s incidental music for The Tempest from 1675. These two juxtaposed musical layers – the latter given by the gut strings and lute of the OAE, the former from the winds, brass and percussion of the Sinfonietta – express Stein’s wartime fascination with Shakespeare’s political plays, which she revisited with Alice B. Toklas in Vichy France.

Goebbels’ work hovers between composition, installation, and music-theatre, playing off the tension between heterogeneous elements; one critic has called his work ‘curatorial composing’. One recent work was Everything that happened would happen, written for the centenary of the First World War, which uses text from Patrik Ouředník’s fragmentary anti-history Europeana alongside a live feed of Euronews, with the choreography devised by chance.

These febrile juxtapositions attempt to grasp the chaotic and oblique experience of history as it is lived, much like Stein’s diaries. Her writings dash from the apparently banal, sugar replaced by honey, to the quietly vulnerable, a chicken squashed by a truck and a family dog euthanised, and the metaphysical: radio announcers’ reflections on their national character.

A ‘staged concert’, it employs a panoply of lighting states on a stage filled with chintzy unheimlich lamps from another time. It’s fair to say that his own musical material isn’t as distinguished as comparable music-theatre works that inspired it – one thinks of De Stijl by Dutch post-minimalist Louis Andriessen, whose style, like Goebbels, is by turns laid-back, jagged, and witty. There is also a long-range link to the unyielding modernist works for reciter and instrumentalists like Schoenberg’s Pierrot Lunaire or A Survivor from Warsaw – the abrasive, appalled phantoms of 19th-century melodrama. Unlike these, Goebbels is cool and ironic, with the playful wit of Stein’s word games frequently coming through. Electronic sounds emerge and recede over both Locke and Goebbels, suggesting a cityscape of drones, sirens, and machines, punctuated by rasping outbursts from brass and woodwinds.

There are moments of strange dreamlike serenity, as in Elizabeth’s Kenny’s wonderful theorbo solo. A curtain-closing tune from Locke segues into an eerie epilogue – a bluesy trumpet threnody accompanied by the otherworldly hum of singing bowls. Repetition is an important ingredient for both Stein and Goebbels, ambivalently tracking towards both activity and sterility, confidence and anxiety; the final trumpet solo, with its cosmic accompaniment, perhaps suggesting some tragic and inescapable cyclicality.

What Goebbels’ music intensifies is the unease lurking behind Stein’s writing. Stein and Toklas remained in Vichy France against advice, as an openly gay Jewish couple, one an avant-garde artist – they could not have been more exposed. Stein was sheltered by keen Petainist Bernard Faÿ and enthusiastically took to translating the leader’s speeches; opinions vary as to the extent that Stein was quite at home in Vichy fascism – plenty of her modernist peers dallied with right-wing authoritarianism – or whether her collaboration was the act of a desperately vulnerable person caught in a very frightening net. Goebbels’ music frames this ambiguity ingeniously in its detached and free-floating way, though perhaps the musicians of the Sinfonietta could’ve sharpened its edges to give us a greater sense of crisis and panic.

Benjamin Britten also had a complex relationship to the Second World War. A pacifist, he spent the first years of the war in the United States, for which he was heavily criticised by the British press; pulled back to Suffolk in 1942 – after reading Crabbe’s poem The Borough – he faced a tribunal as a conscientious objector. A celebrated reputation after the war put him at the centre of British cultural life, though, as his operas make quite clear, he was always in sympathy with people who didn’t fit in, exemplified in his friendship with Rostropovich.

Even this Prom was tinged with controversy. An advert from the Peace Pledge Union was struck from the programme book on account of the BBC’s policy on not hosting political messages. Britten had in fact composed his Pacifist March for the same organisation in the 1930s, as well as a setting of W.H. Auden and Randall Swingler called Ballad of Heroes for left-wing anti-war socialist choirs for a 1939 London gathering.

The War Requiem (1962) was composed to commemorate the rebuilding of Coventry Cathedral, destroyed by bombing. In it he interleaves Wilfred Owen’s poetry with the traditional Latin mass for the dead, often to devastating, ironic effect: Owen’s The Parable of the Father and the Son, his unredemptive retelling of the Abraham and Isaac story, sits in the middle of the Offertorium – ‘Quam olim Abrahae promisisti et semini eius’ – as a bitter testament to the folly of Patriarchs. The Judgment Day trumpets of the Tuba mirum, after a shattering choral climax, melt into Owen’s But I Was Looking at the Permanent Stars: ‘Bugles sang, saddening the evening air’, the baritone sings, shadowed by horn.

It is built from three superimposed layers – a musical version, perhaps, of the Divine Comedy. Angelic children’s voices and soft-focus chamber organ, floating down invisibly from the unreachable heaven of the RAH’s high gallery; the purgatorial souls of the choir and orchestra, whose music begins with the gloomy half-light of the introit – muted, growling, lower strings – grows to an agonised plea for deliverance in the dead march of the Libera me; and the voices of the soldiers on the battlefield, represented by solo baritone, tenor, and chamber orchestra, who live in Hell.

Choral forces impressed in the heavier, declamatory climaxes of the Dies Irae and Libera me, but the half-light of Britten’s orchestration and the music’s ghostly tread, the Quid sum miser or the moaning entries that open the Libera me, call for a more shrouded, covered sound, vowels draped in funereal silk, as befits the Italianate bent of the work’s bigger tableaux; the Sanctus, too, wanted a more operatic resonance and shine from the upper voices.

The very final peroration, though, was exquisitely soft-fringed, with perfectly-shaded dying radiance on the final ‘amen’. The Tiffin Boys’ Choir, prepared by James Day, stole the show, with a soaring, vigorous sound that appeared miraculously from above in a true coup de théâtre. The LSO played ferociously, especially the snarling chamber orchestra, under Pappano’s intense direction; he takes up the post of Chief Conductor next month.

Few can match the wintry brilliance of Galina Vishnevskaya, for whom Britten wrote the soprano line. Her interjections from upstage are like those of an avenging angel. Natalya Romaniw certainly came close, though with a more smouldering, velvety lyricism that keys into the work’s operatic character. Where Vishnevskaya is austere, Romaniw caressed the wandering bluesy line of the Lacrimosa.

We find two soldiers among the ruins of the Libera me – baritone and tenor coming together for an extraordinary setting of Strange Meeting. ‘It seemed from out of battle I escaped’, Allan Clayton sang, fragile and terrified in the spare, blasted musical landscape. Supremely suited to this repertoire, he continues to offer remarkable emotional clarity and colouristic poise. Singing as quietly as he does is a great feat of daring in a venue of that size, and it brings a rare, rapt focus to the audience. ‘Was it for this, the clay grew tall?’, Clayton asked in the Lacrimosa, casting his voice in a pallid light, as he tells his comrades to move a fallen soldier into the sun.

‘I am the enemy you killed my friend’, baritone Will Liverman intoned, wholly unaccompanied, ‘I knew you in this dark’. His instrument was supple enough to give the text its contours and wreathed in sepulchral shadows, if a little smaller in stature than ideal elsewhere. Together, their voices warmed as they duetted ‘let us sleep, now’. The In Paradisum sees all three realms, children, chorus, and soloists, at last joined in music. A shadow falls across its radiance as the dissonant bells of the work’s very opening interrupt this hard-won reconciliation. The final unaccompanied chorus ends with musical resolution, but the silence that follows carries the weight of the world. Pity someone’s mobile went off.

The BBC Proms continue until 14 September.