The personal impact of World War I came out in George Butterworth's A Shropshire Lad, which opened the programme - its composer was killed at the Somme.
Butterworth's pastoral reflections, with ear-caressing solos from concertmaster Wilma Smith and fellow string principals, created the feeling of an elegy afoot.
But there were also tougher pages, which Stier highlighted by giving thrilling climaxes the sort of vigorous workout associated with Richard Strauss.
After interval, Vaughan Williams' 1914 London Symphony was a first for the APO.
A sumptuous score, benefiting from two revisions in 1920 and 1933, it proved a triumph.
Stier caught the generous sweep of its lines, here and there with wafting harmonies familiar from the composer's Tallis Fantasia.
But, despite chirpy local colouring that included harpist Rebecca Harris plucking out the chimes of Big Ben, this is no set of musical picture postcards.
As one writer has commented, the London Symphony deals out moods rather than painting scenes and, when those moods darkened, Stier was at his energetic best.
The unexpected chromatic slashes in the first movement cut through any complacency like a knife; the last movement's stirring march, reflecting a war when the symphony was written, and a Depression when it was last revised, might have had a new chill in its bars for 2014.