Question: When did Germany invade Yugoslavia and Greece?
About the article "World War II", section "Mediterranean (1940–41)".

Candidate passages:
Bulgaria was a German ally, signing the Tripartite Pact on 1 March 1941, their main contribution being transit rights for German units involved against Yugoslavia and Greece.
Bulgaria occupied portions of Greece and Yugoslavia to recreate the 19th century boundaries of Greater Bulgaria, but it did not participate in the Invasion of the Soviet Union.
After the Communist-dominated coup d'état of 9 September 1944, and the simultaneous arrival of Soviet troops in the country, the Bulgarian government declared war on Germany.
Four Bulgarian armies attacked the German positions in Yugoslavia.
An armistice was signed with the Allies in Moscow on 28 October 1944.
After the Nazis fled Yugoslav territory, the 1st Bulgarian Army continued its offensive in Hungary and Austria under the command of General Vladimir Stoychev.
It withstood the Wehrmacht offensive on the Drava River.
Bulgaria's participation in World War II ended when its soldiers met British troops in Klagenfurt, Austriain May 1945.  
On 25 March 1941, fearing that Yugoslavia would be invaded otherwise, Prince Paul signed the Tripartite Pact with significant reservations.
Unlike other Axis powers, Yugoslavia was not obligated to provide military assistance, nor to provide its territory for Axis to move military forces during the war.
Yugoslavia's inclusion in the Axis was not openly welcomed; Italy did not desire Yugoslavia to be a partner in the Axis alliance because Italy had territorial claims on Yugoslavia.
Germany, on the other hand, initially wanted Yugoslavia to participate in Germany's then-planned Operation Marita in Greece by providing military access to German forces to travel from Germany through Yugoslavia to Greece.
Two days after signing the alliance in 1941, after demonstrations in the streets of Belgrade, Prince Paul was removed from office by a coup d'état.
Seventeen-year-old King Peter was declared to be of age, though he was not crowned nor anointed (a custom of the Serbian Orthodox Church).
The new Yugoslavian government under King Peter II, still fearful of invasion, stated that it would remain bound by the Tripartite Pact.
Hitler, however, suspected that the British were behind the coup against Prince Paul and vowed to invade the country.
The German invasion began on 6 April 1941.
Royal Yugoslav Army was thoroughly defeated in less than two weeks and an unconditional surrender was signed in Belgrade on 17 April.
King Peter II and much of the Yugoslavian government had left the country because they did not want to cooperate with the Axis.
While Yugoslavia was no longer capable of being a member of the Axis, several Axis-aligned puppet states emerged after the kingdom was dissolved.
Local governments were set up in Serbia, Croatia, and Montenegro.
The remainder of Yugoslavia was divided among the other Axis powers.
Germany annexed parts of Drava Banovina.
Italy annexed south-western Drava Banovina, coastal parts of Croatia (Dalmatia and the islands), and attached Kosovo to Albania (occupied since 1939).
Hungary annexed several border territories of Vojvodina and Baranja.
Bulgaria annexed Macedonia and parts of southern Serbia.
Further resistance in the Nazi-occupied country was not unified as ideologically opposed resistance groups like the Partisans and Chetniks formed and began making offensives in the Balkans. 
On 28 October 1940, Italy started the Greco-Italian War by launching an invasion of the Kingdom of Greece from Albania.
In part, the Italians attacked Greece because of the growing influence of Germany in the Balkans.
Both Yugoslavia and Greece had governments friendly to Germany.
Mussolini launched the invasion of Greece in haste after the Kingdom of Romania, a state which he perceived as lying within the Italian sphere of influence, allied itself with Germany.
The order to invade Greece was given by Mussolini to Badoglio and Army Chief of Staff Mario Roatta on 15 October, with the expectation that the attack would commence within 12 days.
Badoglio and Roatta were appalled given that, acting on his orders, they had demobilised 600,000 men three weeks prior.
Given the expected requirement of at least 20 divisions to facilitate success, the fact that only eight divisions were currently in Albania, and the inadequacies of Albanian ports and connecting infrastructure, adequate preparation would require at least three months.
Nonetheless, D-day was set at dawn on 28 October.
The initial Italian offensive was quickly contained, and the invasion soon ended in an embarrassing stalemate.
Taking advantage of Bulgaria's decision to remain neutral, the Greek Commander-in-Chief, Lt Gen Alexandros Papagos, was able to establish numerical superiority by mid-November, prior to launching a counter-offensive that drove the Italians back into Albania.
In addition, the Greeks were naturally adept at operating in mountainous terrain, while only six of the Italian Army's divisions, the Alpini, were trained and equipped for mountain warfare.
Only when the Italians were able to establish numerical parity was the Greek offensive stopped.
By then they had been able to penetrate deep into Albania.
The following passage aptly summarizes the episode from the perspective of both the successful Greek defence of their homeland and the ill-prepared Italian debacle:An Italian "Spring Offensive" in March 1941, which tried to salvage the situation prior to German intervention, amounted to little.
The Italian Army was still pinned down in Albania by the Greeks when the Germans began their invasion of Greece on 6 April.
Crucially, the bulk of the Greek Army (fifteen divisions) was left deep in Albania as the German attack approached.
After British troops arrived in Greece in March 1941, British bombers operating from Greek bases could reach the Romanian oil fields, vital to the German war effort.
Hitler decided that he had to help the Italians and committed German troops to invade Greece via Yugoslavia (where a coup had deposed the German-friendly government). 
Hitler began planning to invade Greece in November 1940, after the British occupied Crete and Lemnos.
He ordered the German Invasion of Greece — code-named "Unternehmen Marita" ("Operation Marita") by Germany — on 13 December 1940 for execution in March 1941.
The stated aim of the operation was to prevent the British from getting air bases within striking range of the Romanian oilfields.
On 6 April 1941, the German Army invaded northern Greece, while other elements launched an attack against Yugoslavia.
Breaking through the Yugoslav lines in southern Yugoslavia allowed Germany to send reinforcements to the battlefields of northern Greece.
The German army out-flanked the Greek Metaxas Line fortifications and, despite the assistance provided by a British expeditionary corps, set out to capture the southern Greek cities.
The Battle of Greece ended with the German entry into Athens and the capture of the Peloponnese, although about 40,000 Allied soldiers were evacuated to Crete, prompting one of the largest airborne attacks in the history of warfare: Operation Merkur, or the Battle of Crete. 
Strategically, control of Albania gave Italy an important beachhead in the Balkans: not only did it complete Italian control of the Strait of Otranto and the entrance to the Adriatic Sea, it could be used to invade either Yugoslavia (in tandem with another thrust via Venezia Giulia) or Greece.
In 1939, Count Ciano spoke of Albanian irredentist claims to Kosovo as valuable to Italy's objectives, saying:In October 1940, during the Greco-Italian War, Albania served as a staging-area for Italian dictator Benito Mussolini's unsuccessful invasion of Greece.
Mussolini planned to invade Greece and other countries like Yugoslavia in the area to give Italy territorial control of most of the Mediterranean Sea coastline, as part of the Fascists' objective of creating the objective of "Mare Nostrum" ("Our Sea") in which Italy would dominate the Mediterranean.
But the Albanian army under the command of colonel (later general) Prenk Pervizi abandoned the Italians in combat, causing a major unraveling of their lines.
The Albanian army believed to be the cause of the betrayal was removed from the front.
The Colonel Pervizi and his staff of officials was isolated in the mountains of Puka and Shkodra to the North.
This was the first action of revolt against the Italian occupation.
But, soon after the Italian invasion, the Greeks counter-attacked and a sizable portion of Albania was in Greek hands (including the cities of Gjirokastër and Korçë).
In April 1941, Greece capitulated after an overwhelming German invasion.
All of Albania returned to Italian control, which was also extended to most of Greece, which was jointly occupied by Italy, Germany and Bulgaria.
Italian plans however to annex Chameria to Albania were shelved due strong opposition and ethnic conflict between Albanians and Greeks, as well as opposition by Aromanians to the region being Albanianized.
After the fall of Yugoslavia and Greece in April 1941, the Italian government began negotiations with Germany, Bulgaria, and the newly established client state, the Independent State of Croatia, on defining their borders.
In April Mussolini called for the borders of Albania to be expanded - including annexing Montenegro into Albania that would have an autonomous government within Albania, and expanding Albania's border eastwards, though not as far as the Vardar river as some had proposed - citing that Ohrid should be left to the Slavic Macedonians, regardless of whether Vardar Macedonia would become an independent state or be annexed by Bulgaria.
However the Italian government changed its positions on the border throughout April, later supporting the annexation of Ohrid while giving the territory lying directly outside of Ochrid (including the sacred birthplace of Saint Clement) to the Slavic Macedonians.
After a period of negotiations Italy's new Balkan borders - including Albania's new borders, were declared by royal decree on 7 June 1941.
After the Italian capitulation in September 1943, the country was occupied by the Germans until the end of the war.