Liszt was not yet 20 years old at the time, but the event inspired him to sketch out a Revolution Symphony in five movements. It wasn't until 20 years later when Liszt took the first movement sketch of the symphony and reworked it into a symphonic poem. Revolution spread across most countries in Europe in 1848, including Paris and Liszt's native Hungary.
Kossuth, imposed the Magyar language on all the other nationalities in Hungary. This angered many people, and uprisings followed. Austria took back Hungary after one and a half years of fighting when Russian Tsar Nicholas I marched into Hungary with over 300,000 troops.
Hungary was placed under brutal martial law, with the Austrian government restored to its original position. Liszt's final inspiration to complete the work was to commemorate the execution in 1849 of thirteen Hungarian generals who had led the revolution, but he still left a very short musical quotation from the French national anthem La Marseillaise from the original work in it, perhaps as a tribute to France, his adopted country early in his adulthood.
Liszt wrote a long preface to the work when it was published that dealt with the price paid when violence is part of revolution and the consequences the use of violence has on human progress. It is as if Héroïde funèbre is a funeral oration for the victims of revolutionary violence, no matter what flag they were carrying. Some of Liszt's preface:
De Maistre remarks that over thousands of years it is hard to find any during which, by rare exception, peace reigned on earth - which otherwise resembles an arena where people fight each other as did the gladiators in former times, and where the most valiant salute Destiny as the master and Providence as their judge, before entering the lists. In these wars and carnages that succeed one another like sinister games, whatever the colors of the flags which rise courageous and proud against each other, over both camps they flutter soaked in heroic blood and inexhaustible tears.
Liszt also had this to say about dying for one's country:
I would be the first to answer the call to arms, to give my blood and not tremble before the guillotine, if it were the guillotine that could give the world peace and mankind happiness. But who believes that? We are concerned with bringing peace to the world in which the individual is justly treated by society.
The first version of this piece was published in 1850, with the music written by Liszt but orchestrated by his protege Joachim Raff (as were other of the symphonic poems), as Liszt was still learning the craft of orchestration. But the piece was thoroughly revised and re-orchestrated by Liszt himself in 1854 and 1857.
This was not the only funeral music Liszt wrote. In his set of piano pieces called Harmonies Poétiques et Religieuses the seventh piece named Funérailles is dedicated to those who fell in the Hungarian uprising, perhaps the same thirteen generals who led it. And the Hungarian Rhapsody #5 in E minor is subtitled Héroïde élégiaque. The creative artist in Liszt tried to deal with the death and destruction brought on by people rising up against oppression in the best ways he knew how - he performed many concerts and gave all the proceeds to charities that helped the victims of aggression, and he gave honor and tribute to the fallen through his music.