How could a barb appear here?

[barbertje]

In contradiction to all the know barbarian spawning rules, a barbarian archer appeared 2 tiles north-east of Sigtuna, and moved south-west the same turn, making it impossible to defend the city. How could this happen?

 

[Manco Capac]

Barb teleportation due to the byzantine Great Wall. Given that unclaimed tile is one of the last, that barb that was teleported there.

 

[reddishrecue]

You could've moved the axe from haithabu down south to defend in time.

 

[King Kalmah]

Barb teleportation due to the byzantine Great Wall. Given that unclaimed tile is one of the last, that barb that was teleported there.

Or a border on the other side of the continent was culturally expanded/popped and forced the Barb to the only space of open land left on the map...and unfortunately it was next to your unguarded city borders

when I was a rookie I thought it was the game cheating,but if any other nation has Great Wall and border pops it can be frustrating...

 

[barbertje]

You could've moved the axe from haithabu down south to defend in time.

Didn't work. A barb teleported in this way can move before you can. (probably because it happened when Justinian popped his borders, and the barbs move after that, but before I do.