G minor symphonies like Mozart 's No. 25 often used E flat major for the slow movement , including Haydn 's No. 39 and Vanhal 's G minor symphony from before 1771 ( Bryan Gm1 ) . Another convention of G minor symphonies observed in Mozart 's No. 25 was the choice of E flat major for the slow movement , with other examples including Haydn 's No. 39 and Vanhal 's G minor symphony from before 1771 ( Bryan Gm1 ) .