Years ago, in college, I did a deep dive into researching the oft-overlooked Kushan Empire for a paper. It was a Silk Road empire, its placement setting it up to be a fascinating blend of culture, religion and language. I'd say it was fundamentally Hellenistic but over time the influence of the subcontinent colored its nature considerably. I'm sure I've forgotten more than I remember about its rise and fall, but it was a fascinating study.