The Three Musketeers by Alexandre Dumas Chapter 7 Page 24

besides be abridged if an opportunity should present itself for d’Artagnan to render the king any signal service, or to distinguish himself by some brilliant action. Upon this promise d’Artagnan withdrew, and the next day he began service.

Then it became the turn of Athos, Porthos, and Aramis to mount guard with d’Artagnan when he was on duty. The company of M. le Chevalier Dessessart thus received four instead of one when it admitted d’Artagnan.