3509 early Khazar

[badhabum]

From 650 CE Khazar nobles may be upgraded to CL.

But here is the question : MAT or MUST as it's "all" and not "all or none"

So a mandatory upgrade or an optional one

[lionheartrjc]

Must.  There is no "may" mentioned in the list.  The wording is "Upgrade Khazar nobles (from 650 CE)"

[Onurbm]

Wine quality and subsequently consumption sharply upgraded around this time . Hence changing nobility' behaviour ?