15 March is a national holiday in Hungary, it commemorates the Hungarian Revolution of 1848.
The Hungarian Revolution of 1848 was one of the many European Revolutions of 1848 and closely linked to other revolutions of 1848 in the Habsburg areas. The revolution in the Kingdom of Hungary grew into a war for independence from the Austrian Empire, ruled by the Habsburg dynasty.
After a series of serious Austrian defeats in 1849, the Austrian State came close to the brink of collapse. Thus, the new young emperor Franz Joseph I had to call for Russian help in the name of the Holy Alliance. Czar Nicholas I answered and sent a 200,000 men strong army with 80,000 auxiliary forces. Finally, the joint army of Russian and Austrian forces defeated the Hungarian forces. After the restoration of Habsburg power, Hungary was placed under brutal martial law.
The anniversary of the Revolution’s outbreak, 15 March, is one of Hungary’s three national holidays.