quality:correction, structural:expansion, stylistic:tone
Hungarian Revolution of 1848

Among the various young leaders of the revolution, called Márciusi Ifjak (Youths of March), Petőfi was the key in starting the revolution in Pest. He was co-author and author, respectively, of the two most important written documents: the 12 Pont (12 Points, demands to the Habsburg Governor-General) and the " Nemzeti Dal ", his revolutionary poem.

When the news of the revolution in Vienna reached them on the 14th, Petőfi and his friends decided to change the date of the "National Assembly" (a rally in which a petition to the Hungarian noblemen's assembly would be approved by the people) from 19 March to the 15 March. On the morning of the 15th, Petőfi and the revolutionaries began to march around the city of Pest, reading his poem and the "12 Points" to the growing crowd, which attracted thousands. Visiting printers, they declared an end to censorship and printed the poem and "12 Points".

Crowds forced the mayor to sign the "12 Points" and later held a mass demonstration in front of the newly built National Museum, then crossed to Buda on the other bank of the Danube. When the crowd rallied in front of the Imperial governing council, the representatives of Emperor Ferdinand felt they had to sign the "12 Points". As one of the points was freedom for political prisoners, the crowd moved to greet the newly freed revolutionary poet Mihály Táncsics.

Petőfi's popularity waned as the memory of the glorious day faded, and the revolution went the way of high politics to the leadership of the nobles. Those in the noblemen's Assembly in Pozsony, (today Bratislava) had been pushing for slower reforms at the same time, which they delivered to the Emperor on the 13th, but events had overtaken them briefly. Petőfi disagreed with the Assembly and criticised their view of the goals and methods of the Revolution. (His colleague Táncsics was imprisoned again by the new government.) In the general election, Petőfi ran in his native area but did not win a seat. At this time, he wrote his most serious poem, Az Apostol (The Apostle). It was an epic about a fictional revolutionary who, after much suffering, attempts to assassinate a fictitious king.

Petőfi joined the Hungarian Revolutionary Army and fought under the Polish Liberal General Józef Bem, in the Transylvanian army. The army was initially successful against Habsburg troops, but after Tsar Nicholas I of Russia intervened to support the Habsburgs, it was defeated. Petőfi was last seen alive in the Battle of Segesvár on 31 July 1849, he was supposedly stabbed in the back by a jousting Russian soldier, although his body was never found.