Analysis of information sources in references of the Wikipedia article "Osroene" in Simple English language version.
When the Seleucid Empire disintegrated at the end of the second century BC, its western remnants were annexed to Rome, while several semi-independent kingdoms of decidedly Assyrian identity (Osroene, Adiabene, Hatra, Assur) popped up in the east under Parthian overlordship.
there is no doubt that even before 190 A.D. Christianity had spread vigorously within Edessa and its surroundings and that (shortly after 201 or even earlier?) the royal house joined the church
When the Seleucid Empire disintegrated at the end of the second century BC, its western remnants were annexed to Rome, while several semi-independent kingdoms of decidedly Assyrian identity (Osroene, Adiabene, Hatra, Assur) popped up in the east under Parthian overlordship.