Conversation so far:
What are the Arab kingdoms?
The classical Arab kingdoms were Palmyra, Nabateans, Qedarite, Osroene, and Kingdom of Araba. The later kingdoms are Lakhmids, Ghassanids, and Kindites.
Where were the Arab kingdoms?
Who lived in the Arab kingdoms?
From the beginning of the first millennium BCE, Southern Arabia was the home to a number of kingdoms, such as the Sabaean kingdom

Question: When did the kingdoms originate?
Self-contained rewrite: When did the Arab kingdoms originate?