This symphonic poem, in one movement, was completed in 1857 and belongs to Liszt's later symphonic poems. He began composing Hunnenschlacht in 1855 when the genre of "symphonic poem" had already taken off. More and more composers became interested in this new genre.
[Hunnenschlacht by Wilhelm von Kaulbach, painted in 1837]
The idea for this composition by Liszt came (once again) from Liszt's friend, Princess Sayn-Wittgenstein. She was fascinated by a fresco - a depiction of a historical scene of the great Battle of the Catalaunian Fields in 451 - by German painter Wilhelm von Kaulbach that hung near the steps of the then Berliner Museum until World War II and was painted in 1837. The princess sent Liszt a reproduction of it.
At the battle, a Roman coalition led by General Flavius Aëtius and the Visigothic
King Theodoric tried to stop a savage onslaught by the Hun armies led
by Attila. According to legend, the battle was of such enormous intensity and barbarity that the spirits of the victims were still fighting with each other after their souls had left their bodies. Kaulbach portrays both the heavenly and the earthly element and shows that the Christians eventually overcame the 'savages'. Liszt absolutely wanted to set this fresco to music and he even planned some other musical pieces on historical scenes of Kaulbach which should be named as a cycle 'Weltgeschichte in Bildern und Musik'. But, as with the symphonic poem Heroïde funèbre, he only composed this one symphonic poem.
Hunnenschlacht is so-called "war music." Liszt sets two ideas against each other: the 'savages' (the Huns) are portrayed by a barbaric theme in which this theme is given a Hungarian-sounding twist. In contrast, the civilized Christians, seen here as the defenders of Christianity, are given a theme based on the refrain Crux fidelis from a Gregorian hymn. This hymn is attributed to 6th century bishop Venantius Fortunatus. 'The light of the Christians blinds the pagan savages,' Liszt wrote in his program.
The first section of the piece, marked Tempestuoso, allegro non troppo
carries Liszt's instruction: "Conductors: the entire color should be
kept very dark, and all instruments must sound like ghosts." Liszt
achieves much of this effect by having the entire string section play
with mutes, even in fortissimo passages. This section depicts an
atmosphere of foreboding and suppressed rage before the battle breaks
out.
The second section, Più mosso, begins with a battle
cry in the horns, which is then taken up by the strings. The main
battle theme is then stated, a fully formed version of material from the
very opening. This entire section makes use of the so-called gypsy
scale, which Liszt frequently used in his Hungarian-themed compositions.
In this section Liszt introduces an unusual effect: against the current
of the raucous battle music in the rest of the orchestra, the trombones
play the ancient plainchant melody "Crux fidelis". Liszt's own
description of this section was of "two opposing streams of light in
which the Huns and the Cross are moving." The "Crux fidelis"
theme is later taken up by the strings in a quiet, peaceful contrasting
section.
The tension between the two poles is, of course, resolved at the end of
the piece by an apotheosis in which the Gregorian melody takes center
stage. The music grows in intensity, eventually including an organ and
offstage brass section, and it ends triumphantly.
The
painter, the German Wilhelm von Kaulbach (1805-1874) was mainly noted
as a muralist - his monumental frescoes decorate many walls of public
buildings and palaces in Munich, the city where he was mainly active. He
displayed much creative fertility and was inspired by poems of
Klopstock and Goethe, but also by ancient Greek mythology.
[Includes information from Dutch and English Wikipedia]