St. Francis de Sales overcame a temper problem?

Question

I heard that St. Francis de Sales struggled with a temper problem for many years, but he overcome it. What is the source of this biographical information?

Loiuse M. Stachoople-Kenny's biography, for example, seems to only mention his sweet temper, but nothing about how he fought to overcome his naturally choleric temperament:

Francis never lost his temper, was always patient and good-humoured, submitting with a smile to the constant rebukes of his old tutor, and treating him always with unfailing gentleness and kindness. As a matter of fact, M. Déage really worshipped the very ground his beloved pupil walked on, but like many people, ready to die for those they love, he tantalized and tormented with constant pinpricks, growls and grumbles, the man he loved most on earth; indeed, his affection and his temper would have made life unbearable to anyone less sweet-tempered and kind-hearted than the gentle Bishop of Geneva.

Answer 1

Yes, St Francis did struggled with a temper problem for many years but overcame it. The source of this biographical information is presented in Introduction to Devout Life by St. Francis de Sales (Author), Allan Ross (Editor, Translator):

St Francis by the very constitution of his body was of a lively character and inclined to anger. But having proposed to himself to imitate that Jesus who had said: "Learn of Me, because I am meek and humble of heart" (St. Matt. xi 29), he was able, thanks to the continuous vigilance that he exercised and the violence to which he subjected himself, to repress and curb the motions of the soul to such an extent as to become a living copy of the God of peace and sweetness.

Fr. Alban Buter's biography of him says:

He was indeed naturally of a hasty and passionate temper, as he himself confesses; and we find in his writings a certain fire and impetuosity which renders it unquestionable. On this account from his youth he made meekness his favourite virtue, and by studying in the school of a God who was meek and humble of heart, he learned that important lesson to such perfection, as to convert his predominant passion into his characteristical virtue. The Calvinists ascribe principally to his meekness the wonderful conversions he made amongst them. They were certainly the most obstinate of people at that time, near Geneva: yet St. Francis converted no less than seventy-two thousand of them.