“Oh, ours is a theological quarrel,” replied Aramis, making a sign to d’Artagnan to keep secret the cause of their duel.

Athos indeed saw a second smile on the lips of d’Artagnan.

“Indeed?” said Athos.

“Yes; a passage of St. Augustine, upon which we could not agree,” said the Gascon.

“Decidedly, this is a clever fellow,” murmured Athos.

“And now you are assembled, gentlemen,” said d’Artagnan, “permit me to offer you my apologies.”

At this word apologies, a cloud passed over the brow of Athos, a haughty smile curled the lip of Porthos, and a negative sign was the reply of Aramis.

“You do not understand me, gentlemen,” said d’Artagnan, throwing up his head, the sharp and bold lines of which were at the moment gilded by a bright ray of the sun.  “I asked to be excused in case I should not be able to discharge my debt to all three; for Monsieur Athos has the right to kill me first, which must much diminish the face-value of your bill, Monsieur Porthos, and render yours almost null, Monsieur Aramis.  And now, gentlemen, I repeat, excuse me, but on that account only, and—­on guard!”

At these words, with the most gallant air possible, d’Artagnan drew his sword.

The blood had mounted to the head of d’Artagnan, and at that moment he would have drawn his sword against all the Musketeers in the kingdom as willingly as he now did against Athos, Porthos, and Aramis.

It was a quarter past midday.  The sun was in its zenith, and the spot chosen for the scene of the duel was exposed to its full ardor.

“It is very hot,” said Athos, drawing his sword in its turn, “and yet I cannot take off my doublet; for I just now felt my wound begin to bleed again, and I should not like to annoy Monsieur with the sight of blood which he has not drawn from me himself.”

“That is true, Monsieur,” replied d’Artagnan, “and whether drawn by myself or another, I assure you I shall always view with regret the blood of so brave a gentleman.  I will therefore fight in my doublet, like yourself.”

“Come, come, enough of such compliments!” cried Porthos.  “Remember, we are waiting for our turns.”

“Speak for yourself when you are inclined to utter such incongruities,” interrupted Aramis.  “For my part, I think what they say is very well said, and quite worthy of two gentlemen.”

“When you please, monsieur,” said Athos, putting himself on guard.

“I waited your orders,” said d’Artagnan, crossing swords.

But scarcely had the two rapiers clashed, when a company of the Guards of his Eminence, commanded by M. de Jussac, turned the corner of the convent.

“The cardinal’s Guards!” cried Aramis and Porthos at the same time.  “Sheathe your swords, gentlemen, sheathe your swords!”

But it was too late.  The two combatants had been seen in a position which left no doubt of their intentions.