Question: When did Serbia accept annexation of Bosnia?
About the article "Balkan Wars", section "Reaction in the Balkan States".

Candidate passages:
The Bosnian Crisis of 1908–1909 (also referred to as the "Annexation crisis") erupted into public view when on October 5, 1908, Bulgaria declared its independence and on October 6, 1908, Austria-Hungary announced the annexation of Bosnia and Herzegovina, which was populated mainly by south Slavic nationals (Serbs, Croats and Bosniaks).
Russia, the Ottoman Empire, Britain, Italy, Serbia, Montenegro, Germany and France took an interest in these events.
In April 1909, the Treaty of Berlin was amended to accept the new status quo bringing the crisis to an end.
The crisis permanently damaged relations between Austria-Hungary on the one hand and Russia and Serbia on the other.
The annexation and reactions to the annexation were contributing causes of World War I. 
Even though Bosnia and Herzegovina was still part of the Ottoman Empire, at least formally, the Austrian-Hungarian authorities had factual control over the country.
Austria-Hungary waited for a chance to incorporate Bosnia and Herzegovina formally as well.
Any action concerning Bosnia and Herzegovina depended on international opinion, which Austrian-Hungarian authorities were aware of.
They used the Young Turk Revolution in the Ottoman Empire to finally annex Bosnia and Herzegovina.
The Young Turk movement had gained support in mass protests throughout the Ottoman Empire during 1908, with their intention to restore the suspended Ottoman constitution.
The Austrian-Hungarian authorities were afraid that the revolution could spread to Bosnia and Herzegovina, as it had support from the Bosnian Muslims and the Serbs, who supported the autonomy of Bosnia and Herzegovina within the Ottoman Empire.
On 7 September 1908, the SNO and the MNO demanded that Bosnia and Herzegovina accept the constitution as part of the Ottoman Empire.
On 5 October the Emperor Franz Joseph announced the annexation of Bosnia and Herzegovina and ordered the Minister of Finance to compose a constitution for Bosnia and Herzegovina.
The annexation was announced in Sarajevo two days later, on 7 October.
This annexation led to an international crisis, which was solved on 26 February 1909 when the Ottoman Empire recognised the annexation having received material compensation and on the Austrian-Hungarian garrisons leaving the Sanjak of Novi Pazar.
By this, Bosnia and Herzegovina was formally under the Austrian-Hungarian sovereignty.
On 21 March 1909, the German Empire sent an ultimatum to the Russian Empire to recognise the annexation, which Russia did immediately.
Soon, the Kingdom of Serbia recognised the annexation on 31 March, the Kingdom of Montenegro doing so on 5 April.
The annexation caused unrest amongst the Muslim and Serbian population.
The Muslims could not believe the sovereignty of the Sultan could be overturned with a proclamation, and that they were now ruled by a Christian emperor.
The MNO and the SNO refused to give any official statement about the annexation.
In Budapest they held a meeting on 11 October 1908 they issued the "Message to the People of Bosnia and Herzegovina", where they stated that the people couldn't reconcile with the Austrian-Hungarian occupation in 30 years and asked for the people to remain calm and wait for the decision of the superpowers.
Both parties announced that they would continue the struggle for the autonomy of Bosnia and Herzegovina.
However, since all European countries had already recognised the annexation, the SNO and the MNO, who wanted to continue their activity as legitimate organisations, thus recognised the annexation; the SNO doing so in May 1909 and the MNO in February 1910.
Unlike the Serbs and the Muslims, the Croats enthusiastically accepted the Austrian-Hungarian annexation.
In an audience to the Emperor Franz Joseph, the representatives of the HNZ, Pilar, Nikola Mandić and Antonije Sunarić expressed the gratitude of the Croatian people to the Emperor for the annexation at the end of October 1908.
However, Croatian enthusiasm did not endure, as Bosnia and Herzegovina failed to be joined with Croatia as expected. 
The Bosnian Crisis of 1908–1909, also known as the Annexation crisis, or the First Balkan Crisis, erupted into public view when on 6 October 1908, Austria-Hungary announced the annexation of Bosnia and Herzegovina.
Russia, the Ottoman Empire, Britain, Italy, Serbia, Montenegro, Germany and France took an interest in these events.
In April 1909 the Treaty of Berlin was amended to accept the new status quo bringing the crisis to an end.
The crisis permanently damaged relations between Austria-Hungary on the one hand and Russia and the Kingdom of Serbia on the other.
The annexation and reactions to the annexation were contributing causes of World War I. Serbia and Russia protested to Austria-Hungary taking over Bosnia, but backed down when Germany said it supported Austria-Hungary.
Neither Russia or Serbia were prepared to go to war with Germany.
Austria-Hungary became over confident with Germany's help and escalated the crisis.
Russia was determined not to back down again and hastened its arms build up. 
In October 1908, Austria-Hungary's plans for the annexation of Bosnia and Herzegovina were opposed by Serbia, which sought Russian assistance.
Russia, however, could not comply; a defeat in the Russo-Japanese War had devastated her, and Germany threatened to support Austria-Hungary during a war.
The United Kingdom and France, who were not directly concerned by the annexation, did not become involved.
Thus unaided, Serbia was forced to renounce her opposition to the annexation of Bosnia and Herzegovina. 
At the Congress of Berlin in 1878, the Austro-Hungarian Foreign Minister Gyula Andrássy obtained the occupation and administration of Bosnia and Herzegovina, and he also obtained the right to station garrisons in the Sanjak of Novi Pazar, which remained under Ottoman administration.
The Sanjak preserved the separation of Serbia and Montenegro, and the Austro-Hungarian garrisons there would open the way for a dash to Salonika that "would bring the western half of the Balkans under permanent Austrian influence."
"High military authorities desired [an... immediate major expedition with Salonika as its objective.
"On 28 September 1878 the Finance Minister, Koloman von Zell, threatened to resign if the army, backed by the Archduke Albert, were allowed to advance to Salonika.
In the session of the Hungarian Parliament of 5 November 1878 the Opposition proposed that the Foreign Minister should be impeached for violating the constitution with his policy during the Near East Crisis and by the occupation of Bosnia-Herzegovina.
The motion lost 179 to 95.
The gravest accusations were raised by the opposition rank and file against Andrassy.
Although an Austro-Hungarian side quickly came to an agreement with Bosnians, tensions remained in certain parts of the country (particularly the south) and a mass emigration of predominantly Slavic dissidents occurred.
However, a state of relative stability was reached soon enough and Austro-Hungarian authorities were able to embark on a number of social and administrative reforms which intended to make Bosnia and Herzegovina into a "model colony".
With the aim of establishing the province as a stable political model that would help dissipate rising South Slav nationalism, Habsburg rule did much to codify laws, to introduce new political practices, and to provide for modernisation.
The Austro-Hungarian Empire built the three Roman Catholic churches in Sarajevo and these three churches are among only 20 Catholic churches in the state of Bosnia.
Within three years of formal occupation of Bosnia Herzegovina, Austria-Hungary, in 1881, obtained German, and more importantly, Russian, approval for the annexation of these provinces, at a time which suited Vienna.
This mandate was formally ratified by the Dreikaiserbund (Three Emperor's Treaty) on 18 June of that year.
Upon the accession of Czar Nicholas II, however, the Russians reneged on the agreement, asserting in 1897 the need for special scrutiny of the Bosnian Annexation issue at an unspecified future date.
External matters began to affect the Bosnian Protectorate, however, and its relationship with Austria-Hungary.
A bloody coup occurred in Serbia, on 10 June 1903, which brought a radical anti-Austrian government into power in Belgrade.
Also, the revolt in the Ottoman Empire in 1908, raised concerns that the Istanbul government might seek the outright return of Bosnia Herzegovina.
These factors caused the Austrian-Hungarian government to seek a permanent resolution of the Bosnian question, sooner, rather than later.
On 2 July 1908, in response to the pressing of the Austrian-Hungarian claim, the Russian Imperial Foreign Minister Alexander Izvolsky offered to support the Bosnian annexation in return for Vienna's support for Russia's bid for naval access through the Dardanelles Straits into the Mediterranean.
With the Russians being, at least, provisionally willing to keep their word over Bosnia Herzegovina for the first time in 11 years, Austria-Hungary waited and then published the annexation proclamation on 6 October 1908.
The international furor over the annexation announcement caused Izvolsky to drop the Dardanelles Straits question, altogether, in an effort to obtain a European conference over the Bosnian Annexation.
This conference never materialized and without British or French support, the Russians and their client state, Serbia, were compelled to accept the Austrian-Hungarian annexation of Bosnia Herzegovina in March 1909.
Political tensions culminated on 28 June 1914, when a Bosnian Serb nationalist youth named Gavrilo Princip, a member of the secret Serbian-supported movement, Young Bosnia, assassinated the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand, in Sarajevo—an event that proved to be the spark that set off World War I.
At the end of the war, the Bosniaks had lost more men per capita than any other ethnic group in the Habsburg Empire whilst serving in the Bosnian-Herzegovinian Infantry of the Austro-Hungarian Army.
Nonetheless, Bosnia and Herzegovina as a whole managed to escape the conflict relatively unscathed.
The Austro-Hungarian authorities established an auxiliary militia known as the Schutzkorps with a moot role in the empire's policy of anti-Serb repression.
Schutzkorps, predominantly recruited among the Muslim (Bosniak) population, were tasked with hunting down rebel Serbs (the "Chetniks" and "Komiti") and became known for their persecution of Serbs particularly in Serb populated areas of eastern Bosnia, where they partly retaliated against Serbian Chetniks who in fall 1914 had carried out attacks against the Muslim population in the area.
The proceedings of the Austro-Hungarian authorities led to around 5,500 citizens of Serb ethnicity in Bosnia and Herzegovina being arrested, and between 700 and 2,200 died in prison while 460 were executed.
Around 5,200 Serb families were forcibly expelled from Bosnia and Herzegovina.