Excerpt from the Book "Secret of the Rosary"
A SPANISH COUNTESS, who had been taught the Holy Rosary by Saint Dominic, used to say it faithfully every day with the result that she was making wonderful strides in her spiritual life. Since her one and only thought was how she might attain to perfection she asked a Bishop who was a renowned preacher for some practices that would help her become perfect.
The Bishop told her that, before he could give her any counsels, she would have to let him know the state of her soul and also what her religious exercises were. She answered that her most important exercise was the Holy Rosary which she said every day meditating on the Joyous, Sorrowful and Glorious Mysteries, and that her soul was greatly helped by so doing.
The Bishop was overjoyed to hear her explain what priceless lessons the mysteries contain. "I have been a Doctor of Theology for twenty years," he exclaimed "and I have read many excellent books on various devotional practices. But never before have I come across one better than this----for it is of the essence of Christianity and is a devotion which cannot but bear fruit. I shall follow your example, and from now on I shall preach the Rosary."
The Bishop's preaching met with great success, for in almost no time his diocese changed for the better. There was a notable decline in immorality and worldliness of all kinds as well as in gambling. There were several striking instances of people being brought back to the Faith, or sinners making restitution for their crimes and of others sincerely resolving to give up lives of vice. Religious fervor and Christian charity began to flourish. These changes were all the more remarkable because this Bishop had been striving to reform his diocese for some time but with hardly any results.
To better inculcate devotion of the Rosary, the Bishop also wore a beautiful Rosary at his side and always showed it to the congregation when he preached. He used to say:
"My dear brethren in Jesus Christ, I am a Doctor of Theology and a Doctor of Canon as well as Civil law, but I say to you, as your Bishop, that I take more pride in wearing Our Lady's Rosary than in any of my episcopal regalia or academic robes."
Source: http://www.catholictradition.org/Classics/secret-rosary38.htm