While alive everyone in Puthenchira and surrounding villages regarded Mariam Thresia to be a saint. The people also believed that even as she went about helping them in their need like an angel of mercy, she would help them also from heaven. Lots of people had received healing from sickness, couples received children, marriages were settled, many received homes and lands, loans got sanctioned, court cases were settled, few received visions and wise counsels from Mother Mariam Thresia. Few versions of miracles, and graces received through the intercession of St. Mariam Thresia spread to people like tiding of waves in the sea, attracting more and more devotees to pray and intercede.
Thus in 1973 Bp. Joseph Kundukulam appealed to the Sacred Congregation of the Saints, Rome and on 6 June, 1975 directed by the Sacred Congregation, Rome, he appointed a Historical Commission. He appointed Rev. Fr. Sion OCD as the Postulator and Rev. Fr. Antony Tharakan as the Vice Postulator for the Cause of Mother Mariam Thresia. The Commission submitted its report by 12 July 1978.
As part of the Diocesan inquiry, the canonical exhumation to identify the grave of Mariam Thresia took place on 3 January 1981. Bishop Pazhayattil of Irinjalakuda presided over the rite of exhumation, flanked by Mar Joseph Kundukulam, Bishop of Trissur, and Mar JosephIrimpen, Bishop of Palghat. Besides, there were present two official witnesses, two doctors, several ecclesiastics, the superior general and all the provincials of the Congregation of the Holy Family. In 1985 the Scared Congregation, Rome, declared that the cause of Mariam Thresia as valid.
On 28 June 1999, with the declaration of the decree the Servant of God Mariam Thresia became entitled to be called Venerable. Venerable Mother Mariam Thresia bore her title only for nine months till her beatification on 9 April 2000. A miracle approved by all of the healing of Mathew Pellissery’s congenital club feet which had taken place in 1970-1971 was used for the same. A boy of 14/15 years was instantly cured of his club feet, the right foot in 1970 and the left foot in 1971, each time after a long period of prayer and penance offered by the whole family.
The cause of canonisation preceded from the miracle of healing of a baby in 2009. When he was born, Christopher was not expected to survive. He had underdeveloped lungs and three holes in his heart. When he began experiencing respiratory failure, doctors gave up hope for his life. Christopher’s grandmother brought a relic of St. Mariam Thresia from her home to the hospital to place beside him, and the family prayed through her intercession. Christopher is now ten years old. In addition to the first miracle he was healed of his speech impediment at the age of three and legs at the age of four.
The people of Puthenchira, the home village of St. Mariam Thresia, have been celebrating her birthday on 26 April every year in her house with special prayers and Holy Mass. They carry the sacred light, in procession on foot, from the tomb at Kuzhikatussery, in view to the celebration. The Holy shrine Kuzhikattussery, celebrates her death anniversary on 8 June every year. The celebration is precede by novena for nine days in preparation, followed by a High Mass on 8 June. People from across Kerala and outside reach in ten thousands to the Shrine on that day, they partake in the procession and community meal followed by the solemn Eucharistic celebration.
Since her beatification in 2000, the feast of Bl. Mariam Thresia was celebrated in the Syro-Malabar Church. Devotion to Bl. Mariam Thresia had spread far wide to all continents since the sisters of Holy Family Congregation with the Charism of Bl. Mariam Thresia have spread to all the corners. In 2019 she was declared a Saint in Holy Catholic Church by Pope Francis in Vatican along with four others .
Sr. Udaya Kallukaran Chf