The significance of Vidovdan 28

St Vitus 1498, from the Nuremberg Chronicle

Vidovdan is a Serbian religious holiday, St. Vitus' Day, whose feast is celebrated on June 28th every year (Gregorian Calendar, June 15 according to the Julian Calendar, which is still in use by the Serbian Orthodox Church). It is a Slava (Patron saint feast day) of St. Vitus, heavily connected in Serbian culture to the historic Battle of Kosovo, among other events.
The feast day is sacred to ethnic Serbs (Serbian Orthodox Christians), who transformed the pagan Slavic god of war, fertility and abundance "Svetovid" into the Sicilian martyr, St. Vitus, who exorcized the evil out of Diocletian's son, at the time of the final Christianization of the Serbs during the rule of Basil I (867 - 886) by Byzantine missionaries of Constantinople Cyril and Methodius.

Through the centuries, events which were significant turning points in Serbian history which at first just happened to occur on Vidovdan, such as the Battle of Kosovo, have become powerful sources for spiritual strength and patriotism which resonate to the present day.
Vidovdan has long been considered a date of special importance to ethnic Serbs and the Balkans, and because of this a surprising number of historic events have occurred on this date, it was perhaps no  coincidence that Gavrilo Princip assassinated the Austro-Hungarian Archduke Franz Ferdinand in Sarajevo on the 28th June 1914, triggering the First World War. Some occurrences, such as this, can be said to be clearly by convenient design, others appear to be quite amazing coincidences -or are they? The following events each took place on Vidovdan 28, but are expressed here in the Gregorian Calendar, any reporter reading this - it may be worthwhile in the future to keep an eye on the Balkans on 28th of June every year, you never know what might happen.

The Battle of Kosovo
On June 28, 1389, the Ottoman Empire fought against Serbia in the Battle of Kosovo, and Serbian Prince Lazar was slain in battle. Ottoman Sultan Murad I was killed by Serbian knight Miloš Obilic. The Battle of Kosovo was a draw, yet in the wake of it the Serbs were left with too few men to effectively defend their lands, while the Turks had many more troops in the east. Consequently, the Serbian principalities that were not already Ottoman vassals, one after the other became so in the following years.
The Battle of Kosovo came to be seen as a symbol of Serbian patriotism and desire for independence in the 19th century rise of nationalism under Ottoman rule, and its significance for Serbian nationalism returned to prominence during the breakup of Yugoslavia and the Kosovo War when Slobodan Miloševic invoked it during an important speech.

On June 28, 1914 the assassination of the Austro-Hungarian crown prince, Franz Ferdinand and his wife, in
Sarajevo by Bosnian Serb nationalist Gavrilo Princip led to the outbreak of the First World War. It is quite probable that the assassins chose Vidovdan to assassinate the Archduke to heighten its cultural and symbolic impact.

On June 28, 1919, the Treaty of Versailles was signed, ending World War I. Seemingly purposefully concluded on 28th June to mark exactly five years since the Assassination of the Archduke. Although a German delegation had travelled to Versailles on the 29th April 1919 to potentially sign the treaty but had thrown it out due to its unacceptability, and it took two month  and another coalition government before it was signed in July.

King Alexander I of Serbia
On June 28, 1921, the Serbian King Alexander I proclaimed the new Constitution of the Kingdom of Serbs, Croats and Slovenes, known thereafter as the Vidovdan Constitution (Vidovdanski ustav).

On June 28, 1948, the Cominform (Communist Information Bureau) published, on the initiative of its Soviet delegates Zhdanov, Malenkov and Suslov, in a "Resolution on the State of the Communist Party of Yugoslavia" their condemnation of the Yugoslavian communist leaders - this happening is seen as the date that marks the final split between the Soviet Union and Yugoslavia.

On June 28, 1989, on the 600th anniversary of the battle of Kosovo, Serbian leader Slobodan Miloševic delivered the Gazimestan speech at the site of the historic battle. The speech was delivered to a huge crowd gathered at Gazimestan in the Central Kosovo. It came against a backdrop of intense ethnic tension between ethnic Serbs and Albanians in Kosovo and increasing political tensions between Serbia and the other constituent republics of the then Socialist Federal Republic of Yugoslavia.
The speech has since become famous for Miloševic's reference to the possibility of "armed battles", in the future of Serbia's national development. Many commentators have described this as presaging the collapse of Yugoslavia and the bloodshed of the Yugoslav Wars. Miloševic actually spoke of the "battles" in the context of "implementing economic, political, cultural, and general social prosperity" and himself later said that he had been misrepresented

On June 28, 2001, Slobodan Miloševic was deported to ICTY (International Criminal Tribunal for the former Yugoslavia) located in The Hague to stand trial.

On June 28, 2006, Montenegro was announced as the 192nd member state of the United Nations.

On June 28, 2008 was the inaugural meeting of the Community Assembly of Kosovo and Metohija. The assembly of the association of local governments created by the municipal authorities in Kosovo elected in the May 11, 2008 municipal elections called by the Government of Serbia. It was created in Kosovska Mitrovica (North Kosovo) to represent the municipalities that defy the 2008 Kosovo declaration of independence. The Assembly is composed of 45 representatives delegated by 26 municipalities. The majority of delegates are ethnic Serbs, while some represent Gorani, Bosniak and Romani communities.