Hmm, if Rome is trading with the Chinese and Indians heavily then they must have some good relations with the Kushan Empire. So if Parthia ever became too much of a problem they could always ally with the country they are most definitely trading with.
Yes, the Romans (and the Indian Company) has strong contacts with the Kushan Empire ITTL. But it's quite hard to coordinate foreign policies between the Kushans and the Roman Empire because of the ancient lines of communication and the slowness of information. However, I can tell you that the Kushan Empire will still play a major role in the TL.
Also it seems this new guy seems to want to prove his place in history and you're spoiler about Scythia is leading me to believe Astrakhan will Finally be Roman! (even though as a city it didn't exist yet but it is still a very fertile and fortifiable region.
Well, the Goths are on the western bank of the Black Sea in Sarmatia/Ukraine (threatening Dacia and Moesia/Romania and Bulgaria). So the Roman armies will focus on the Odessa/Sewastopol: I don't think that the Romans will have the power to conquer everything up to the Volga

- do you think so?
And with a wall across the small distance between the Don and Volga rivers (or even a Canal?) you got a good amount of land for forestry and agriculture as well as some primetime land on both the coast of the Black and Caspian Sea
Wait, where do you got these information? The Rostov and the Volgograd region may be very fertile, but the Astrakhan are consists mainly of steppe. And I don't see where do you find the forests and the superb land on the coast of the Caspian Sea.
No, he did not. You may review his route more closely. Smart young Alexander never crossed the two big iranian deserts (Kavir, Lut).
Well, but he marched through the Alborz and the Hindu Kush, and a comparable army could do the same to reach Persia through Bactria or Arachosia.
These deserts are indeed almost uncrossable with huge armies. But in between the 2 big deserts on the plateau, there is a half desert, which is manageable for steppe hordes and such. However the route is pretty clear and at least controllable, so that surprises should not happen. Of course you can always take the northern route via Parthia to Hyrcania or Media. But now you have to pass some pretty deadly bottlenecks, like the Caspian Gates. Of course you can pass them, if no Leonidas waits for you, but you loose time to invade a well defended Media. Time, 2 huge roman armies can use to move into position.
Hm, once Persia was reorganized by the Romans, I will come up with a map of Roman defense positions in the various Iranian mountain ranges like Aborz and Zagros. It's good news that the main part of Persia consists of deserts like Kavir, Lut or Makran (ancient Gedrosia) that haven't to be defended.
Ok, I guess, you have been such exited about your great Indian Company and this worthless dynasty you described, that you forgot about the the real interesting part: the roman frontiers.
The Company isn't great, but wait for the effects of the capital the Company is bringing into the Empire and of the technology transfer.
Also, the dynasties aren't worthless, since I love to create the characters of different emperors raised in different environments and to imagine what sort of consequences their socialization process has on their reign.
PS: Well, the very most interesting part would have been the roman constitution.
The Roman constitution... Well, all legislative, executive and judiciary power is vested in the emperor.
The Senate consists of some aristocrats, but mainly of military officials born into the Equestrian Order.
Any other questions?
I am still waiting for your hints, why these romans in your TL should not ruin their empire and destroy themselves.
Well, until now there weren't any major civil wars because:
- the dynastic links weren't disrupted
- the Ears (created by the Severans) are controlling all important officials and can stop most of the conspiracy/usurpations
- the usurpers who manage to mobilize some forces are stopped by the Central Army (the Imperial retinue)
PS: There was another wall. Between the western Caspian Sea and the Caucasus. Not as impressing but still great. These Parthians did a lot of great stuff which is highly underrated. However #1 are the chinese, #2 the parthians , and the romans are just #3 if it comes to walls. No doubt about that.
PPS: I am not sure, if some of these walls were buildt by the Sassanids. So don't blame me, praising the Asarcids. However, there were more people, than the chinese, beeing better than the romans in building walls.
But how did the Parthians manage to man these walls without a standing army? Can a feudal state like Parthia build and maintain such a wall? I suppose that the walls were created by the Parthians, but upgraded by the more centralized Sassanians.
They are not intersted to expand into such a dangerous area like Parthia. Or even worse Bactria.
The Romans aren't interested in these areas? Why not? I would love to include a Roman Alexander in the timeline, even if Rome looses these areas soon after the conquest.
Arians are a sect of Christianity. I think the word you are looking for is Aryans.
At least I escaped from all this sect stuff by butterflying away Christianity

But I have to write something about Buddhism in the next posts... There is so much stuff to write about
Awesome! Just finished and it is very well written. Some things are a bit implausible but well nothing is perfect. I hope you continue!
THX!
THIS-IS-ROOOOOOOOOOOOOOME!
THIS-IS-ROOOOOOOOOOOOOOOME
with Mesopotamia!
Next update tomorrow, I have to change some things because of the helpful feedback.