East of the Vistula was classed as Sarmatia.

Entity and relation annotations:
id: 0
type: entity
value: text: East of the Vistula
labels: <Location>
id: 1
type: entity
value: text: Sarmatia
labels: <Location>
type: relation
to_id: 1
labels: Location:located_in:Location
from_id: 0