Complex sentence: As Chief, Spotted Elk (later became known by the name of "Big Foot" or Sitȟáŋka) was considered a great man of peace and was best known among his people for his political and diplomatic successes.
Split into simpler sentences: As chief, Spotted Elk (who later became known by the name of "Big Foot" or Sitȟáŋka) was considered a great man of peace. He was best known among his people for his political and diplomatic successes.