Anna Maria Redi was born to a noble Tuscan family at Arezzo — descendant of the great Tuscan scholar Francesco Redi — and was educated by the Benedictine nuns of Florence. At seventeen, in 1764, she entered the Discalced Carmelites of the monastery of Santa Teresa in Florence and took the religious name Teresa Margherita of the Sacred Heart.
Her religious life lasted just over five years. From her vows in 1765 onward she experienced a deep but completely hidden interior life — for which her superiors and fellow nuns recognized in her an unusual personal sanctity but had no external phenomena to point to. The recorded prayers she left, of which the most famous is the cordial-prayer of consecration to the Sacred Heart of Jesus, focus on the hidden silent life of God in the soul, on the interior crucifixion that no external observer can see, and on the mystical-liturgical reality of the Sacred Heart devotion that the previous century's Margaret Mary visions had brought to the universal Catholic Church.
She died at the monastery on March 7, 1770 at twenty-two, of a sudden gastric haemorrhage. Her body remained incorrupt; the post-mortem examination found her heart cardio-vascularly extraordinary. The cult, encouraged by her sisters at the Florence monastery, grew slowly through the 19th century. Canonized 1934.