From November 14 to November 22, 1908 the Congress of Manastir (Albanian: Kongresi i Manastirit) was held with the goal of standardizing the Albanian alphabet. Prior to the Congress, the Albanian language was represented by a combination of six or more distinct alphabets, plus a number of sub-variants. November 22 is now a commemorative day in Albania, Kosovo, and North Macedonia.
As benign as it sounds, it was quite controversial. Prior to the Congress, the Ottomans, wanting to defend their sovereignty, demanded that Albanians formally declare themselves as Ottomans and adopt an Arabic-based alphabet. Rather than revolution, the Congress was convened where Muslims, Orthodox, and Catholic scholars debated the formalization of the Albanian language. Finally, a compromise was reached with an alphabet with elements from both the Arabic and Latin scripts.
The Congress of Manastir represents one of the most important events for Albanians, not only because of the decisions made, but also because those decisions were legally implemented by the Ottoman authorities. In 2008, festivities were organized in Bitola, Tirana, and Pristina to celebrate the centenary of the congress.
See how Albania celebrates the day here.