Marcus Aurelius

To Turn The Tide.

Temporal displacement involves place name change. "Vienna, Austria" had been and becomes again "Provincia Pannonia Superior, Imperium Romanum."

Artorius' first meeting with Emperor Marcus Aurelius gets a massive buildup. In CHAPTER FIFTEEN, Marcus Aurelius discusses Artorius while still in Rome. In CHAPTER SEVENTEEN, Marcus Aurelius discusses Artorius after he has travelled to Vindobona in the Province of Pannona Superior. In CHAPTER EIGHTEEN, Artorius reflects that he is about to meet someone whose life and death he has studied and whose books he has read, then does meet him. The Emperor closely resembles his own face on coins and statues. Artorius quotes a book that Marcus Aurelius has not written yet and presumably will not write, or not in the same way, in this new timeline. 

This has to be a classic of time travel fiction.

(It was fortunate not only that the merchant Josephus who found the newly arrived and defenceless time travellers did not kill and rob them but instead helped them and treated them with respect but even that they had arrived near a road where they could be and were discovered immediately. However, my friend Andrea informs me that it is inappropriate either to entreat or to thank Fortuna.)