“Is that what a Roman fortress here looked like?” Steve asked. “It resembles the temporary camps we saw the Roman legions build in Germany, but this one looks permanent. I thought the Romans would build something more impressive than this.”

“This is a post-Roman construction,” said Harriet. “The village on the plateau is fortified in part by unmortared stone, including Roman masonry brought from elsewhere. The gatehouse has touches of Roman architecture, too. But the overall design is Celtic.”

“You mean now that the Romans don’t rule here anymore, the Britons are doing everything their way again?”

“In practical matters, Britons never forgot their own traditions,” said Harriet. “Further, funding was an issue. Roman administrators at the height of their power could pay many men to quarry, move, and cut stone, and hire others to build with it. Post-Roman Briton rulers had to make do with ramparts of rammed earth.”

Steve nodded. She pointed to a similar hill much farther in the distance to the north. “That’s Glastonbury Tor. It still exists in our own time, as well.”

“So with the Romans gone, the Britons are back where they started in fighting the Saxons?” Steve asked. “Except for what you said about Roman cavalry tactics?”

“Not completely. The Britons still have some advantages from their Roman cultural experience, including roads, cities, and towns. However, hordes of Saxons have already settled along the eastern coast.”

“You said this Artorius, who uses Roman cavalry tactics, is the historical basis for King Arthur. Back in Room F-12, we agreed to pretend we wanted to sell horses to him. So he rules here? Or what?”

“Artorius is a charismatic cavalry captain with some Roman-style training. He has become Riothamus, or High King, of the Britons by leading the Celtic fight for their homeland against the Saxons.”

“If the Saxons landed on the eastern coast, along the English Channel, why is he here?” Steve asked. “If we’re in what’s central southern England in our own time, then we’re a long way from the Channel.”

“That’s right,” said Harriet. “You see, the Saxons have been coming for many decades. They have conquered and settled considerable territory on the eastern side of Britain.”

“All right, I get it. Now the Britons are fighting the Saxons along some boundary that runs through the middle of the country.”

“Yes. Of course, the boundary is jagged and uneven, usually represented by rivers or ridges. And because of constant fighting, it is in flux throughout these years. Artorius had to establish his base far enough behind the border to have a wide buffer zone.”

Steve nodded. “Since the Saxons are on foot, it would take them a lot longer to march all the way here than it would take his cavalry to ride out to meet them.”

“Correct.”

“Hunter, I have to ask you the question that comes up in every mission,” said Steve. “We know that MC 6 will return to full size around here somewhere, but exactly what’s he going to do? Where should we look for him?”

“That is usually Jane’s area of expertise, of course,” said Hunter. “Without a roboticist to call upon, I will have to make a judgment. Based on my experience in how Jane has made her earlier appraisals, I expect that MC 6 will want to stop the war between the Britons and the Saxons that causes so much suffering.”

“Yeah, that sounds like what she’d say,” said Steve. “We found MC 3 and MC 4 trying to stop wars, too. Of course, we prevented that.”

“We must prevent MC 6 from doing it, as well,” said Hunter. “According to the history I took from the city library, Artorius held the Saxons at bay during his lifetime but they eventually overwhelmed his successors. If MC 6 succeeds in working out a long-term settlement, however, the England of medieval, Renaissance, and ultimately modern times will never develop, deeply changing the course of history.”

“Oh, piddle.” Harriet laughed lightly. “That possibility is preposterous.”

“It is?” Steve looked at her in surprise. Her bluntness startled him. “Why?”

“You see, the Saxons, Angles, and Jutes invaded Britain because of tremendous population pressure on the Continent north of the Roman Empire and their displacement by the movement of more powerful tribes, such as the Franks and the Goths.”

“Why did they come to Britain in particular?” Steve asked. “Couldn’t changes in what happens here cause them to go somewhere else?”

“As a matter of fact, they moved into Gaul in this era, as well, to settle on the Loire,” said Harriet. “But by comparison, Britain was lightly populated at the time. The desperation of the Saxons to migrate and the comparatively modest numbers of the Britons to protect their island dictated this period of British history. No agreement among individuals could stop these forces.”

“That makes sense to me,” said Steve. He liked the logic of this argument. It fit the fact that the team’s appearance in the past on other missions had not, to their knowledge, disrupted their own time.

“I have already acknowledged that I cannot measure the degree to which chaos theory can be applied to history,” said Hunter. “And I accept this history as accurate. However, the First Law requires me to consider the danger of changing history, no matter how remote it may be. After all, as a robot, MC 6 can expect a much longer life than any human, barring injury. If we do not take him away soon enough, he can remain in this time to continue working out compromises as new hostilities develop. Of course, in any case we have to take him before he reaches the time he left and explodes with nuclear force.”

“You ‘re the boss, as I said earlier,” said Harriet. “I’m just doing my duty as your historian in reporting my opinions to you.”

“As far as our search is concerned, the First Law would still impel MC 6 to attempt an end to war, no matter how hopeless his long-term chances are,” said Hunter. “Following the judgment that Jane made about earlier component robots, I believe this imperative would take him to Artorius or maybe even the Saxon leaders.”

“I have no argument with that,” said Harriet. “You would know more about robots.”

“I also feel that the creation of Arthurian legend will almost certainly change if the history upon which the earliest chroniclers based it no longer occurs in the same way. This is possible even if the historical events do not change. The legend seems to be quite important in British culture and its branches in the United States and other parts of the former British Empire.”

“Now, that I agree with,” Harriet said emphatically. “Arthurian legend-of course it could change if historical events alter. That legend has had great cultural influence over the centuries and must not be allowed to change.”

“I wouldn’t want to lose it, either,” said Steve. “I followed it as a kid-the stories of Camelot and the Knights of the Round Table, and Lancelot and Guinevere.”

“Of course, we will not find them here,” said Hunter. “They are legend, not history.”

“So we agree with you about not letting MC 6 change history after all,” said Harriet. “We will find him.”

“I guess if Ishihara had responded to your call, you’d have told us by now,” said Steve.

“That is correct,” said Hunter. “I have heard nothing.”