28 May. Republic Day honors the date on which the Azerbaijan Democratic Republic was founded on 28 May 1918 as the first secular democratic state in the Muslim East. Our people every year celebrate this day a great interest. Because on that day - May 28, 1918 - Azerbaijan, which had lost its independence after the Gulustan and Turkmenchay treaties, living in colonial terms for more than a century, being prohibited its culture, language, and religion, had been released. The Declaration of Independence of Azerbaijan is the declaration of independence of the Azerbaijan Democratic Republic from the Russian Empire. Azerbaijan was proclaimed independent in Tiflis on 28 May 1918.

The Azerbaijan Democratic Republic, founded by Mammad Amin Rasulzadeh, was the first parliamentary republic and the first democratic, legal and secular state in the Turkish and Islamic world. Among the important accomplishments of the ADR was the extension of suffrage to women, making Azerbaijan one of the first countries in the world, and the very first majority-Muslim nation, to grant women equal political rights with men. The first state, which officially recognized the Democratic Republic of Azerbaijan was the Ottoman Empire. That historic event took place on June 4, 1918. On November 9, 1918, on the basis of the proposal by Mammad Amin Rasulzadeh the three-color flag of the Democratic Republic of Azerbaijan was accepted

Until then the flag of the Democratic Republic of Azerbaijan was red. The Democratic Republic of Azerbaijan was able to operate in a tense and complicated socio-political situation for only 23 months. The Soviet Union invaded Azerbaijan on 28 April 1920. Though the idea of independence was not defeated, and in 1991, after the collapse of the Soviet Empire, Azerbaijan again declared its independence.