Complex sentence: Kapodistrias called on the British and French residents to support him in putting down the rebellion, but this they refused to do, but Admiral Richord (or Ricord) took his ships north to Poros.
Split into simpler sentences: Kapodistrias called on the British and French residents to support him in putting down the rebellion, but this they refused to do. Nonelethelss, an Admiral Richord (or Ricord) took his ships north to Poros.