Complex sentence: As a written language, it benefited from the fact that Bearn was an independent state from the mid XIVth century up to 1620: bearnese was used in legal and administrative documents long after most other gascon (and/or occitan) provinces were joined to France.
Split into simpler sentences: As a written language, it benefited from the fact that Bearn was an independent state from the mid XIVth century up to 1620. Bearnese was used in legal and administrative documents long after most other Gascon (and/or Occitan) provinces were joined to France.