Question: When did Kogalniceanu proclaim Romania's independence from the Ottoman Empire?
About the article "Romania", section "Holidays".

Candidate passages:
The first official contact between Mexico and Romania was in April 1880 when then Prince Carol I sent a letter to President Porfirio Díaz informing him of Romania's independence from the Ottoman Empire by the Treaty of Berlin in 1878.
Both nations established official diplomatic relations on 20 July 1935, however, diplomatic relations were severed by Mexico on 24 December 1941 when Romania joined the axis powers during World War II.
Diplomatic relations were re-established on 20 March 1973 by both nations and soon afterwards embassies were opened in both nations capitals respectively. 
The "de jure" independence of Bulgaria (, "Nezavisimost na Balgaria") from the Ottoman Empire was proclaimed on in the old Bulgarian capital Tarnovo by Prince (Knyaz) (afterwards Tsar) Ferdinand of Bulgaria.
Bulgaria has been Europe's tenth oldest country by continuous sovereignty since that date.
Bulgaria had been a widely autonomous ("de facto" independent) principality since , when it was liberated from Ottoman rule in the wake of the Russo-Turkish War of 1877–1878.
On 6 September 1885, it had unified with the Bulgarian-majority Ottoman autonomous province of Eastern Rumelia.
After the Liberation, Bulgaria's main external goal was the unification of all Bulgarian-inhabited areas under foreign rule into a single Bulgarian state: the main targets of Bulgarian irredentism are Macedonia and southern Thrace, which continued to be part of the Ottoman realm.
In order to join an anti-Ottoman alliance and claim those territories by war, however, Bulgaria had to proclaim its independence first.
This would constitute a violation of the Treaty of Berlin's terms, an act unlikely to be approved by the Great Powers.
The chaos that ensued in the Ottoman Empire following the Young Turk Revolution of 1908 provided suitable conditions for the Bulgarian proclamation of independence.
Many of the Great Powers had also abandoned their support for the Ottomans, looking for territorial gains instead: Austria-Hungary was hoping to annex Bosnia and Herzegovina, the United Kingdom was looking to seize the empire's Arab territories in the east, and the Russian Empire's main target was control over the Turkish Straits.
In September 1908 at a meeting in Buchlov (, contemporary Czech Republic), envoys of Austria-Hungary and Russia supported each other's plans and agreed not to hinder Bulgaria's proclamation of independence which was likely to take place.
Towards the middle of September, the democratic government of Aleksandar Malinov had decided that the suitable moment was near.
, Ferdinand arrived at Rousse from a break in his Hungarian mansion.
He was awaited there by the government to discuss the final decision on board the "Krum" ship.
The delegation then took the train to Tarnovo, where the official proclamation would take place.
According to recent research, it was at the Dve Mogili railway station that the manifesto of independence was completed on .
The independence of Bulgaria was formally proclaimed at the SS.
Forty Martyrs Church in Tarnovo.
As a result, Bulgaria's status was promoted to that of a kingdom, increasing its international prestige.
Ferdinand would adopt the title of Tsar instead of a Knyaz and the country would be ready to join the Balkan League and fight the Ottoman Empire in the First Balkan War of 1912–1913.
Bulgaria's declaration of independence was followed by Austria-Hungary's annexation of Bosnia the following day and Greece's union with the Cretan State (unrecognized until 1913).
With the two countries' joint violation of the Treaty of Berlin and the dominant support among European countries, the independence of Bulgaria was internationally recognized by the spring of 1909.
The Ottoman Empire did not demand any financial compensation from Bulgaria because Russia cancelled the Ottomans' outstanding reparations for the war of 1877–1878.
Bulgaria, however, did have to pay 82 million francs to Russia as a consequence.
The de jure independence is celebrated annually on 22 September as Bulgaria's Independence Day.
On 22 September 2008, Bulgaria celebrated the centenary anniversary of its independence. 
Between 1821 and 1832, Greek revolutionaries fought a war for Greek Independence from the Ottoman Empire. 
Since 2013, there are 14 non-working holidays.
In Romanian language, the consecrate Christian holidays have untranslatable correspondents, such as "Rusalii" (Pentecost), "Dragobete" (Valentine's Day) and "Florii" (Palm Sunday).
Nowadays, the National Day of Romania, a legal non-working holiday, is December the 1st, celebrated by military marches and manifestations across the country.
It commemorates the 1918 assembly of the delegates of all ethnic Romanians held in Alba Iulia, when the Union of Transylvania with the Kingdom of Romania was declared upon.
During the communist regime, the national day was August the 23rd, marking the 1944 royal coup d'état by King Michael I when he decided about the dismissal and arrest of general Ion Antonescu, Romanian Prime Minister and Leader of the State.
On the same day he ordered the immediate cessation of Romania's collaboration with the Axis Powers, the beginning of negotiations for an armistice with the Allies and a military cooperation with the Soviet Union.
A certain segment of Romanians, who support the reinstatement of the monarchy, prefers the date of May 10 to be the National Day, as it used to be between 1866–1947.
On May 9, 1877, prime minister Kogălniceanu proclaimed the Principality of Romania's independence from the Ottoman Empire, a status recognized by the European powers in the Treaty of Berlin in 1878.
The Ottoman delegation expressed the wish that ‘Transcaucasia should proclaim its independence and announce its form of government before the negotiations then under way were completed.'
The Ottoman Empire wanted to break down the barrier between Anatolian Muslims and Caucasian Muslims and to ‘consolidate the unity between kindred nations.’ The Ottoman Empire’s special tasks in the Caucasus, Rauf Bey reassured, reflected links between the Empire and the Caucasian peoples that were "...not only historical and geographical, but rather ones of blood, flowing from their common past."
A. Pepinov, an advisor to the Transcaucasian delegation and a member of the Muslim National Council, suggested setting up a fourth, separate administrative unit consisting of the Muslim areas of the Batum and Kars regions.
‘The bonds created by their similarities of race, religion, economy and everyday life are very strong and it will be very hard for them to exist without each other’,’ Pepinov argued in ‘grounding’ that wish.