10 kingdoms

The "10 kingdoms" in the Bible, mentioned in Revelation 17:12, refer to ten kings who will rule together for a short time, receiving power from the beast. These kingdoms are distinct from the seven heads (empires) of the beast, which represent historical periods. The ten kingdoms are not successive rulers in the past but rather a confederacy of ten states that will emerge at the beginning of the tribulation, possibly encompassing nations in Western Europe, says BibleRef.com. 

Here's a more detailed breakdown:

Revelation 17:12:

This verse describes the "ten horns" as ten kings who have not yet received royal power but will receive authority as kings for one hour, together with the beast.

Not Successive:

The ten kingdoms are not a series of historical rulers but rather a simultaneous group of kings who will rule together, according to BibleRef.com.

Future Confederacy:

The ten kings are seen as representing a confederacy of ten states that will arise at the beginning of the tribulation.

Possible Location:

Some interpretations suggest these kingdoms may be in Western Europe, encompassing nations that were once part of the Roman Empire, according to BibleRef.com