The last sister professed by Archbishop Leonard Neale before his death was Sister Mary of Jesus Mattingly, who was born in 1784 in St. Mary's county, Maryland. She was somewhat worldly in her youth, but after attending a retreat when she was 22 or 23, she concluded that earthly pursuits were empty, and began working toward the sanctification of her soul by various exercises of devotion. She could do this only as far as her health would permit, however, because she had been of "a weak constitution" since childhood. After several years of perseverance practicing the devout life, she wanted to enter a religious order, but her relatives were opposed. Her father objected particularly, as there was another young daughter at home. She loved her father very much, and over time her prayers and constant entreaties prevailed and he consented at last, but he wept about it. She was sympathetic, but at the same time she also worried that he might revoke his consent, so she came eagerly to our monastery to ask admittance. This was readily granted, for the Sisters knew her merits, and several of them had known her even before they had entered religious life.
She edified everyone during her time in the novitiate by demonstrating submission to her director and the other superiors by her exact observance of the rule. She made her vows on May 8, 1817, becoming the last religious personally professed by Archbishop Leonard Neale, who died just over a month later.
She was known for her amiability, and although she restrained her natural vivacity in an appropriate manner, it was part of her character. She loved the sisters so much that she frequently said that she could perceive no fault in them. Although she was quite intelligent and could have handled any office of the house except that of Assistant Superior, her delicate health kept her in her status of associate sister. (Note: Associate Sisters were not obliged to recite the Divine Office sung in Latin in the choir, which occupied at least two hours in a sister's day. That prayer was replaced with more simple devotions such as the Rosary which could be prayed anywhere.)
She developed tuberculosis (then known as "consumption," and the same ailment that took Sister Mary Charity McAtee and many other sisters.) She was so ill that she never enjoyed a day's health. She took to her bed, an although she was failing, when the last sacraments were administered she received them with "lively devotion." She was indifferent to her own state and confident in God throughout her last moments. She retained her faculties until the last, making "acts and ejaculations" to God and calling on Our Lady and her other patron saints to assist her. When someone asked if she were resigned to die, she answered, "I desire nothing more, since such is the will of God." A few minutes later, "she yielded her happy soul to the hands of Him who created it. It was the evening of the 17th of April, 1818." She was 33 years old.