As his wife was most anxious to meet her mother, it was nevertheless finally arranged that Queen Isabella should make the journey; but he excused himself, on account of the multiplicity of his affairs, from accompanying her in the expedition.

The Duke of Alva was, accordingly, appointed to attend the Queen to Bayonne.
Both were secretly instructed by Philip to leave nothing undone in the approaching interview toward obtaining the hearty co-operation of Catharine de Medici in a general and formally-arranged scheme for the simultaneous extermination of all heretics in the French and Spanish dominions.

Alva's conduct in this diplomatic commission was stealthy in the extreme.

His letters reveal a subtlety of contrivance and delicacy of handling such as the world has not generally reckoned among his characteristics.

All his adroitness, as well as the tact of Queen Isabella, by whose ability Alva declared himself to have been astounded, proved quite powerless before the steady fencing of the wily Catharine.
The Queen Regent, whose skill the Duke, even while defeated, acknowledged to his master, continued firm in her design to maintain her own power by holding the balance between Guise and Montmorency, between Leaguer and Huguenot.