In the last week of March, three days before he defined the character of ‘Operation Barbarossa’ to his generals, Hitler received some highly unwelcome news with consequences for the planning of the eastern campaign. He was told of the military coup in Belgrade that had toppled the government of Prime Minister Cvetkovic and overthrown the regent, Prince Paul, in favour of his nephew, the seventeen-year-old King Peter II. Only two days earlier, in a lavish ceremony on the morning of 25 March in Hitler’s presence in the palatial surrounds of Schloß Belvedere in Vienna, Cvetkovic had signed Yugoslavia’s adherence to the Tripartite Pact, finally — following much pressure — committing his country to the side of the Axis. Hitler regarded this as ‘of extreme importance in connection with the future German military operations in Greece’.93 Such an operation would have been risky, he told Ciano, if Yugoslavia’s stance had been questionable, with the lengthy communications line only some twenty kilometres from the Yugoslav border inside Bulgarian territory.94 He was much relieved, therefore, although, he noted, ‘internal relations in Yugoslavia could despite everything develop in more complicated fashion’.95 Whatever his forebodings, Keitel found him a few hours after the signing visibly relieved, ‘happy that no more unpleasant surprises were to be expected in the Balkans’.96 It took less than forty-eight hours to shatter this optimism. The fabric of the Balkan strategy, carefully knitted together over several months, had been torn apart.
This strategy had aimed at binding the Balkan states, already closely interlinked economically with the Reich, ever more tightly to Germany. Keeping the area out of the war would have enabled Germany to gain maximum economic benefit to serve its military interests elsewhere.97 The initial thrust was anti-British, but since Molotov’s visit to Berlin German policy in the Balkans had developed an increasingly anti-Soviet tendency.98
Mussolini’s reckless invasion of Greece the previous October had then brought a major revision of objectives. The threat posed by British military intervention in Greece could not be overlooked. The Soviet Union could not be attacked as long as danger from the south was so self-evident. By 12 November Hitler had issued Directive No. 18, ordering the army to make preparations to occupy from Bulgaria the Greek mainland north of the Aegean should it become necessary, to enable the Luftwaffe to attack any British air-bases threatening the Romanian oil-fields.99 Neither the Luftwaffe nor navy leadership were satisfied with this, and pressed for the occupation of the whole of Greece and the Peloponnese. By the end of November, the Wehrmacht operational staff agreed.100 Hitler’s Directive No.20 of 13 December 1940 for ‘Operation Marita’ still spoke of the occupation of the Aegean north coast, but now held out the possibility of occupying the whole of the Greek mainland, ‘should this be necessary’.101 The intention was to have most of the troops engaged available ‘for new deployment’ as quickly as possible.102
With the directive for ‘Barbarossa’ following a few days later, it was obvious what ‘new deployment’ meant. The timing was tight. Hitler had told Ciano in November that Germany could not intervene in the Balkans before the spring.103 ‘Barbarossa’ was scheduled to begin in May. When unusually bad weather delayed the complex preparations for ‘Marita’, the timing problems became more acute. And once Hitler finally decided in March — following earlier military advice, as we have seen — that the operation had to drive the British from the entire Greek mainland and occupy it, the campaign had to be both longer and more extensive than originally anticipated.104 It was this which caused Hitler, in opposition to the strongly expressed views of the Army High Command, to reduce the size of the force initially earmarked for the southern flank in ‘Barbarossa’.105
