Very early on the morning of October 10, 1989, President Richard von Weizsacker of West Germany and a few aides stepped through the Berlin Wall near the Brandenburg Gate and entered no man's land. They almost froze when, after a few moments, they saw approaching them an army lieutenant of the East German border police.
He was clearly as confused as they were by the previous night's scenes of unbridled joy, when the Wall had been breached eights hours before schedule. He kept interrupting his purposeful stride until, abreast of them, he froze in indecision, his hand near his gun.
Only a newly arrived Australian television crew, quite unaware of the momentousness of the scene and the players they were filming, witnessed the sequence.
The lieutenant hesitated before he slowly drew his hand to his temple in salute: 'Welcome, Mr President, everything is going to plan no reports of any disturbances.'
This formal but friendly recognition of the federal president's authority symbolised the coming together of the two German peoples and states after 40 years of division. Almost exactly a year later, on Wednesday, he will solemnly seal the restoration of German unity and sovereignty at a grand ceremony in Berlin's Philharmonia Hall.
The Wall, provisionally made of barbed-wire, had been erected in the night of 12-13 August 1961 by the Communist regime of Walter Ulbricht. The world, above all the people of Berlin, were outraged but did nothing; Harold Macmillan, the British Prime Minister, typically, saw no reason to leave the grouse-moors of Scotland.
Its construction and the West's look-away reaction, especially that of Konrad Adenauer, the first federal Chancellor, brought to a temporary end any lingering dream of German unification. This dream had survived during the bitter years of occupation after Hitler's defeat, the year-long Berlin blockade of 1948-49, the formation of two separate states in 1949 at the start of the Cold War, the bloody repression of the June 1953 uprising in East Germany and the collapse of numerous but half-hearted attempts by the four victorious wartime powers to resolve the German Question.
The history of Germany in the last 45 years is the history of a divided Europe. It is the uneven development of two states and societies, politically, economically and socially, a process of growing apart criss-crossed by one of their coming together. And, even this week, it remains incomplete.
The critical period was the decade after the war when the West decided to rebuild the western half of Germany and Europe as a bulwark against the Soviet Union, and a shining example of democratic freedom and economic success.
Adenauer is credited by Helmut Kohl, the first all-German Chancellor since Admiral Donitz (who held that officer for a brief week after Hitler's suicide) as the father of today's German unity. But Adenauer's route to unity lay through integration with the West as a separate state joining Nato and, later, helping to found the EEC.
Ironically, in view of today's political arguments, it was the Social Democrats in opposition who most vociferously attacked him for making unity a secondary priority. This reached its apogee in the furore over Stalin's Notes in 1952.
In March 1952, only a year before Stalin's death, he sent the first of three notes proposing unification, a peace treaty with Germany and the removal of all occupying forces. The price, rejected by Adenauer above all, was neutrality. The federal republic was engaged in concluding treaties with the three Western allies (the Germany Treaty) and with West European neighbours, apart from the UK, in the European Defence Community.
Historians differ to this day over whether Stalin's offer was genuine or whether it was yet another attempt to delay Western integration, economic and military, and hence further his expansionist plans. But, either way, the offer fell because the West could not accept in the end his terms for free elections without UN control.
An apparently final opportunity for resolving the German Question was passed over when, on June 17, 1953, as tens of thousands on the streets of East Berlin and other East German cities demanded free all-German elections and better living standards, Walter Ulbricht, his own police unable to cope, called on Soviet troops to put down, bloodily, the greatest challenge to his state so far.
The repression that followed, however, did not kill off the popular demand for freedom, democracy and well-being. As the federal republic entered the years of the economic miracle under Ludwig Erhard, East Germans continued to flee to the West. Between the founding of the state in May 1949 and the building of the Wall in August 1961 around 2.5 million settled in West Germany.
The dominant reality between then and October 1989, when East Germany celebrated its 40th anniversary just before its impending collapse, was two-statedness.
In a keynote speech in July 1963 the prominent Social Democrat, Egon Bahr, proposed what was be the dominant theme of the following decade and more: Wandel durch Annaherung (change through rapprochement).
The speech at a Protestant college in Tutzingen marked the start of what was to become Willy Brandt's Ostpolitik after the Social Democrats took office in 1966, the highlights of which were the 1970 journey to Erfurt to meet, amid cheering crowds, Willi Stoph, the East German Premier, and the signing of the treaties with Poland and the Soviet Union.
The critical argument now is whether this entire process, including formal mutual recognition by the two Germanies in 1972-73, delayed and impeded unification.
As events after the Wall came down proved, Germany and its citizens on either side of the border were the main beneficiaries of President Gorbachev's decision to set in train the dissolution of the Soviet empire. All plans for preserving two states in a new guise, such as a confederation, were swiftly rendered redundant by popular will and Helmut Kohl's seizure of the hour.
But this week, even as Germany celebrates its restored unity and sovereignty, the 40-year legacy remains. East Germany may have effectively ceased to exist with monetary union on July 1 this year but, many Germans believe, it will take at least another decade before its former citizens and their Western brothers and sisters are socially and economically a cohesive whole.