Complex sentence: The term "ash-Sheikh" refers to the ancestor of the family, the Islamic religious reformer Muhammad ibn Abd al-Wahhab, who was known as "the Sheikh", a term of respect for a noted elder, teacher or religious leader.
Split into simpler sentences: The term "ash-Sheikh" refers to the ancestor of the family, the Islamic religious reformer Muhammad ibn Abd al-Wahhab, who was known as "the Sheikh". In Arabia, in this context, "Sheikh" is a term of respect for a noted elder, teacher or religious leader.