In the spring the Lutheran peasantry revolted, sick of being harried, of being hungry, sick most of all of their arrogant Emperor. They swept across Upper Austria, delirious with success, unable to believe their own strength. By early summer they were at the walls of Linz. The siege lasted for two months. The city had been ill-prepared, and was quickly reduced to horse meat and nettle soup. Kepler's house was on the wall, and from his workroom he could look down across the moats and the suburbs where the fiercest fighting took place. How small the protagonists looked from up here, and yet how vivid their blood and their spilled guts. The smell of death bathed him about as he worked. A detachment of troops was quartered in his house. Some among them he recognised from the printing house. He had thought his children would be terrified, but they seemed to regard it all as a glorious game. One morning, in the midst of a bitter skirmish, they came to tell him that there was a dead soldier in his bed.

"Dead, you say? No, no, he is wounded merely; your mama put him there to rest. "

Cordula shook her head. Such a serious little girl! "He is dead, " she said firmly. "There is a fly in his mouth. "

Towards the end of June the peasant forces breached the wall one night and set fire to a section of streets before being repulsed. Plank's shop was destroyed, and with it all the sheets of the Tables so far printed. Kepler decided it was time to move. By October, the siege long since lifted and the peasants crushed, he had packed up everything that he owned and was on his way to Ulm, excommunicate and penniless, never to return.

In Ulm for a while he was almost happy. He had left Susanna and the children in Regensburg, and, alone once more after so many years, he felt as if time had magically fallen away and he was back in Graz, or Tübingen even, when life had not properly begun, and the future was limitless. The city physician Gregor Horst, an acquaintance from his Prague days, leased him a little house in Raben Alley. He found a printer one Jonas Saur. The work went well at first. He still imagined that the Tables would make his fortune. He spent his days in the printing house. On Saturday nights he and Gregor Horst would get quietly drunk together and argue astronomy and politics into the small hours.

But he could not be at rest for long. The old torment was rising once more in his heart. Saur the printer lived up to his name, and there were quarrels. Yet again Kepler turned his hopes toward Tübingen and Michael Mästlin; could Gruppenbach, who had printed the Mysterium, finish off for him the Tables? He wrote to Mästlin, and getting no reply he set out for Tübingen on foot. But it was February, the weather was bad, and after two days he found himself halted at a crossroads in the midst of turnip fields, exhausted and in despair, but not so far gone that he could not see, with wry amusement, how all his life was summed up in this picture of himself, a little man, wet and weary, dithering at a fork in the road. He turned back. The town council at Esslingen presented him with a horse, got from the town's home for the infirm. The beast bore him bravely enough to Ulm and then died under him. Again he saw the aptness of it, this triumphal entry, on a broken-down jade, into a city that hardly knew him. He made his peace with Jonas Saur, and at last, after twenty years, the Tables were hauled to completion.

Two kinsmen of Tycho Brahe called on him one day at his lodgings in Raben Alley, Holger Rosenkrands the statesman's son and the Norwegian Axel Gyldenstjern. They were on their way to England. Kepler considered. Wotton, King James's ambassador to Prague, had urged him once to come to England. Rosenkrands and Gyldenstjern would be happy to take him with them. Something held him back. How could he leave his homelands, however bad the convulsions of war? There was nothing for him but to go to Prague. He had the Tables at least to offer the Emperor. It was not likely it would be enough. His time was past. Even Rudolph in his latter days had grown bored with his mathematician. But he must go somewhere, do something, and so he took himself aboard a barge bound for the capital, where, unknown to both of them, Wallenstein awaited him.

Now, baking his chilblains at Hillebrand Billig's fire, he brooded on his time in Sagan. It had been at least a refuge, where for a while he had held still, the restlessness of his heart feeding vicariously on his new master's doings. Wallenstein's world was all noise and event, a ceaseless coming and going to the accompaniment of distant cannonades and hoofbeats at midnight: as if he too were in flight from an inexorable demon of his own. Yet Kepler had never known a man who so fitted the shape and size of his allotted space. What emptiness could there be in him, that a stalking devil would seek for a home?

Billig was laboriously doing the tavern accounts at the kitchen table, licking his pencil and sighing. Frau Billig sat near him, darning her children's stockings. They might have been done by Dürer. A draught from the window shook the candlelight. There was the sound of the wind and the rain, the muffled roars of the Saturday night revellers in the tavern, the crackling of the fire, the old dog's snores, but beneath all a deep silence reigned, secret and inviolable, perhaps the silence of the earth itself. Why, dear Christ, did I leave home to come on this mad venture?

At first he had been wary of Wallenstein. He feared being bought for a plaything, for the general's obsession with astrology was famous. Kepler was too old and too tired to take up again that game of guesswork and dissimulation. For months he had held back, worrying at the terms Wallenstein was offering him, wanting to know what would be required of him in return. Conversation, said Wallenstein, smiling, your company, the benefit of your learning. The Emperor, with ill-concealed enthusiasm, urged him to accept the offered post, and took the opportunity to transfer on to Wallenstein the crown's considerable debt to its mathematician. Wallenstein made no protest; his blandness caused Kepler's heart to sink. Also the astronomer would be granted an annual stipend o: 1,000 florins from the Sagan coffers, a house at Gitschin where the general had his palace, and the use of a printing press with sufficient paper for whatever books he might wish to publish, all this without condition or hindrance. Kepler dared to hope. Could it be, at last, could it be..?

It could not. Wallenstein indeed believed he had purchased a tame astrologer. In time, after many clashes, they had come to an arrangement whereby Kepler supplied the data out of which more willing wizards would work up the horoscopes anc calendars. For the rest he was free to do as he wished. He saw no sign of the imperial debt being settled, nor of the printing works and the paper that had been promised. Things might have been worse. There was the house at least, and now and then he was even paid a little of his salary on account. If he was not happy, neither was he in despair. Hitzler's word came back to him: tepid. Sagan was a barbaric place, its people peculiar and cold, their dialect incomprehensible. There were few diversions. Once he travelled down to Tübingen and spent a gloriously tipsy month with old Mästlin, deaf and doddering now but merry withal. And one day Susanna came to him, with a look of mingled amusement and surprise, to announce that she was pregnant.

"By God," he said, "I am not so old then as I thought, eh?" "You are not old at all, my dear, dear Kepler." She kissed him, and they laughed, and then were silent for a moment, a little awkward, almost embarrassed, sharing an old complicity. What a happy day that had been, perhaps the best out of all the days of that amused and respectful, ill-matched and splendid marriage.