On the eighth of September, nineteen forty one, German forces cut the last road into Leningrad, and the city was surrounded.
It stayed surrounded for eight hundred and seventy-two days. That is two years, four months and two weeks, and it is the longest siege of a major city in the Second World War.
About two and a half million people were inside the ring, and around four hundred thousand of them were children.
The plan was not to capture the city. The orders that survive are explicit that a surrender was not to be accepted. The plan was to seal it and wait.
The first winter was the worst thing that happened to any European city during the war, and there is no honest way to make it comfortable.
Food ran out. By late November the daily bread ration for a person not doing manual work was a hundred and twenty-five grams, which is a slice and a half, and the bread was not entirely bread, because it was being extended with cellulose and whatever else could be made to hold together.
There was no heating, because there was no fuel, in a winter that reached minus thirty. There was no electricity for most of the city, and after the pipes froze there was no running water, so people went down to the Neva with buckets and cut holes in the ice.
Something approaching a million civilians died in Leningrad during the siege, the great majority of them from starvation, and most of those in that first winter.
That is the fact this episode sits on top of, and it is not going to be described any further than that, because the rest of the story is what people did anyway.
There was one gap in the ring, and it was not a road. It was a lake.
Lake Ladoga is enormous, the largest lake in Europe, and its far shore was still in Soviet hands. In the autumn, supplies came across by barge, under air attack, in small quantities.
Then in November the lake began to freeze, and somebody had the idea of driving on it.
Engineers measured the ice thickness continuously and worked out what weight it would take. The first horse-drawn sledges went over in late November. Then lorries, at first half-loaded, then fully loaded, then towing sledges behind them to spread the weight.
Drivers ran the route day and night. They drove with the cab door tied open, so that if the ice went they might get out. Some of them made the round trip, thirty kilometres each way, twice a night for weeks. There were traffic controllers standing on the ice in the dark, and repair stations, and anti-aircraft guns mounted on the frozen surface, and lorries that went through and lorries that were bombed, and the ones behind drove around the holes and kept going.
It was officially the Military Motor Road, and nobody called it that. Everybody called it the Road of Life.
Over the winter it brought in enough to raise the ration, and it took out well over half a million people, mostly children and the sick, in the other direction.
Dmitri Shostakovich was thirty-four and the most famous composer in the Soviet Union, and he was in Leningrad when the ring closed.
He volunteered for the army and was refused because of his eyesight, so he joined the fire watch instead, and there is a well-known photograph of him in a fireman's helmet on a roof of the conservatory.
And in between shifts, he was writing a symphony.
He wrote the first three movements in Leningrad during the first months of the siege, in an apartment with the windows taped, working between air raids. In October he was ordered out of the city by air, with his family, and he finished the fourth movement in Kuibyshev on the Volga in December.
It is his Seventh Symphony, and he dedicated it to the city.
It premiered in March nineteen forty two, far away, and then in Moscow, and then it went abroad. The score was photographed onto microfilm and flown to Tehran, then driven to Cairo, then flown on to New York, and by the summer of nineteen forty two it was being played all over the world by orchestras who had never seen Leningrad.
Everywhere except in Leningrad, which had not heard a note of it.
The city had one orchestra left, the Radio Committee Orchestra, because everybody else had been evacuated.
In the spring of nineteen forty two its conductor, Karl Eliasberg, was told to perform the Seventh Symphony in Leningrad, and he sent out a call for his musicians to report.
Fewer than half came. Accounts differ on the exact number, but of an orchestra of around a hundred, something like fifteen were still alive and able to play.
So they advertised. Notices went up asking any musician still in the city to come forward. Players were recalled from the front line, in uniform, and given leave to attend rehearsals. Some arrived from the trenches with instruments they had carried with them.
The first rehearsal lasted fifteen minutes, because that was as long as they could play. Musicians fainted. The percussionist could not carry his own drum to the hall. Eliasberg himself was so weak that he was brought to rehearsals on a sledge.
They were given extra rations, which was a serious decision in a city where rations were a matter of life, and they rehearsed for two months, and three of them died before the performance.
The concert was set for the ninth of August, nineteen forty two.
That date was chosen deliberately, and the reason is one of the better pieces of spite in the war. German plans captured earlier had named the ninth of August as the day a victory banquet would be held in the Astoria Hotel in the centre of Leningrad, and invitations had reportedly been printed.
There was an obvious problem, which is that a concert hall full of people is a target, and the German artillery could reach the city centre easily.
So the Soviet commander, Leonid Govorov, arranged an artillery operation for that evening. Three thousand shells were fired at German gun positions and observation posts in the hours before and during the concert, specifically to keep them silent. It was given a codename, Squall, and its objective was to protect a piece of music.
The hall was full. The audience were people from the city, in their best clothes, which by then hung on them.
And the performance was broadcast on the loudspeakers that were mounted throughout the streets, so that the whole city heard it. It was also, on Eliasberg's request, broadcast from loudspeakers pointed outward, across the lines, at the German positions.
Years afterwards, German soldiers who had been sitting out there described hearing it. One of them said that it was then that they understood they would never take the city, because the people inside it were not going to die the way they were supposed to.
The siege was fully lifted on the twenty-seventh of January, nineteen forty four. Eliasberg lived until nineteen seventy eight. Some of the musicians from that night were still alive and being interviewed in the nineteen nineties, and several of them said the same thing: that they had not played it well, technically, and that it did not matter in the slightest.
What the symphony means is still argued about. It is usually described as being about the invasion, and Shostakovich allowed that description. Later, privately, he said the piece was about more than one kind of thing being crushed, and about his own city before the war as well. He lived in a country where saying such things aloud was dangerous, and he spent his whole career writing music that could be heard two ways.
There is a diary from the siege kept by a girl called Tanya Savicheva, a few pages long, in which she recorded the dates her family members died, one line each. It is in a museum in St Petersburg. It is the shortest thing in this series and the hardest to read.
Here is something to think about tonight. Rations were given to musicians so that they could rehearse, in a city where a slice of bread was the difference between living and not. Somebody had to decide that a concert was worth that. Do you think they were right?