Possible Clues:

• Appropriating
• Aramis companion
• The first of three musketeers could have had a shot at this
• Greek monastic mountain
• Count de la Fère in Dumas novels
• Greece's 'Holy Mountain'
• His last case better remembered than his first
• Name adopted by the Comte de la Fère
• Nineteen letters including h (for height)
• Colleague of Porthos, Aramis