Geevarghese Mar Dionysius of Vattasseril popularly known as Vattasseril Thirumeni (31 October 1858 – 23 February 1934) was a bishop of the Malankara Church and 15th Malankara Metropolitan. In 2003, the Church declared Mar Dionysius as a saint. He is known as 'The Great Luminary of Malankara Church' (Malayalam: Malankara Sabha Bhasuran), a title which the Church bestowed on him in recognition of his contribution to the Church.^[1]

Geevarghese was born in Vattasseril family, the fifth child of Joseph Vattasseril of Mallappally and Aleyamma, Kolathu Kalathil of Kurichy, on 31 October 1858. Among his siblings, Ouseph Punnoose was also a priest. Following his elementary education at C. M. S. Middle School in Mallappally he completed his high school education from C. M. S. High School, Kottayam.^[2] On 12 October 1876, while still a high school student, he was ordained as a sub-deacon by Patriarch of Antioch Ignatius Peter III at Puthuppally St. George Church.^[3]

He studied at the Orthodox Theological Seminary (Old Seminary or Pazhaya Seminary), Kottayam for four years. He acted as the secretary to Gregorios Geevarghese of Parumala. Geevarghese soon became a great Syriac scholar under the careful tutelage of St. Gregorios, who taught him at Parumala Seminary. He also learned Theology and Syriac language from Metropolitan Baselios Paulose I at Monastery of Saint Thomas, Vettikkal. On 16 October 1879, the sub-deacon Geevarghese was ordained as a full deacon^[2] and on 18 January 1880 he was ordained to priesthood by St. Gregorios himself. For some time, Fr. Geevarghese oversaw the theological education at Parumala Seminary. As per the existing tradition, he had been ordained for Parumala Seminary. During the period 1881–1908 he was the manager of the Seminary. In 1895, Fr. Geevarghese accompanied St. Gregorios on his visit to the Holy Land along with Paulose Ramban.

He was an outstanding orator who was well aware of the importance of the vitality and Christian persuasiveness of the Bible when delivering the speeches to the faithful. Prayers and fasting were the pillars of his spiritual foundation. In addition to the liturgical hours of prayer, he spent much time in private prayers and silent meditations behind closed doors. In spite of his busy schedule, he was also able to focus on three to four lessons from the Holy Bible every day. Despite of the many spiritual qualities he shared leadership qualities like domineering charisma and progressive mindedness. The church recognizes him as a living saint of his time on earth.^[2]

Mar Dionysius VI and his fellow clergies have played a central role in elevating the primate of Malankara Orthodox Church to the title Catholicos of the East. By establishing the Catholicate in Malabar, the visionary Metropolitan succeeded in defending the sovereignty and independence of the St. Thomas Christians of India. Mar Dionysius VI also prepared a first draft of the Church Constitution with the aid of Patriarch Ignatius Abdul Masih II and of using his profound knowledge in the Canons of the Church. This draft was used to prepare the Church Constitution of 1934. In his last encyclical, he wrote to the entire Malankara Church:

And I commit in each of you the responsibility to upkeep that institution which most of you along with myself truly believe to be indispensable for the survival, prosperity and progress of our Church, and which has been till now painstakingly guarded by all of us, namely the Catholicate.

Dionysius VI experienced physical suffering on 13 February 1934, and suffered from paralysis on 16 February. Still, the Metropolitan had clear memory. On 21 February, Baselios Geevarghese II administered him the service of Anointing. Two days later, Dionysius VI died on 23 February 1934, and was buried the next day in the Chapel of Old Seminary, Kottayam, near the tombs of his predecessors.

In his speech that day, Baselios Geevarghese II said:

On this first Saturday of the Great Lent, on this day of remembrance of the global Malpan Mar Aprem, the great Malpan of Malankara has entered eternal rest. On this day of remembrance of the Martyr St Thevodoros who laid his life for our Lord, our Metropolitan, who is eligible to be called Confessor for suffering similar persecution for the Church, is being interred.

Dionysius VI was exalted as a saint and confessor to the faithful. On the 69th feast day of Dionysius VI (24 February 2003), he was canonized by the Episcopal Synod of Malankara Orthodox Church headed by Baselios MarThoma Mathews II, Malankara Metropolitan and Catholicos of the Malankara Church. St. Dionysius is the second Indian Saint to be canonized by the Malankara Orthodox Syrian Church. The Catholicos Baselios Geevarghese II might have foreseen this when he instructed the sentence "The time will not dim his glory" to be engraved on the tomb of Dionysius VI. 23 February is observed as the saint's feast day.

Honoring the Saint's memory, several churches and educational institutions have been established including St. Dionysius Church, Perukavu (Trivandrum), St. Dionysius Church^[7] in Al Ain, United Arab Emirates, St. dionysius orthodox church Desertland, Dammam (under diocese of Thrissur), St. Dionysius Indian Orthodox Church, Auckland, New Zealand,^[8] St. Dionysius Orthodox Church, Dasarahalli,^[9] Bangalore, St. Dionysius Orthodox Chapel, Aravali (Gurugram) and Dionysius Senior Secondary School in Mallappally, Kerala,^[10] to name a few. M. G. D. Ashram^[11] (monastery) at Panayampala, Kerala was founded in 1980 with St. Dionysius as its Patron Saint. The Ashram has an orphanage (Balabhavan) in its care since 2000.

• Samuel, Rev. Dr. V. C. (1986). Truth Triumphs: Life and Achievements of Metropolitan Mar Dionysius VI. M. O. C. Publishers, Kottayam, India.
• Cheeran, Rev. Dr. Joseph; Kottackal, K. V. Mammen; Pulikkottil, Adv. P. C. Mathew (February 2002) [2001]. വട്ടശ്ശേരിൽ തിരുമേനി: മലങ്കരസഭയുടെ കോട്ട (ജീവചരിത്രം) [Vattasseril Thirumeni: The Fortress of Malankara Church (Biography)] (PDF) (in Malayalam) (3rd ed.). Kottackal Publishers, Manganam, Kerala.
• Kochukoshy I. A. S., C. K. (February 2011) [1994]. ധീരോദാത്ത വിശുദ്ധൻ [The Saint with Exemplary Courage] (PDF) (in Malayalam) (2nd ed.). St. Dionysius Foundation, Kottayam, Kerala.
• Paret, Z. M. (1965). വട്ടശ്ശേരിൽ മാർ ദിവന്നാസ്യോസ് [Mar Dionyisus Vattasseril]. മലങ്കര നസ്രാണി (Malankara Nasraani) (in Malayalam). J. M. Chemmarappally, Kottayam.
• Paret, Z. M. (1965). നിത്യാക്ഷരങ്ങൾ [Eternal Letters]. മലങ്കര നസ്രാണി (Malankara Nasraani) (in Malayalam). J. M. Chemmarappally, Kottayam.
• Chandanappally, Dr. Samuel. വട്ടശ്ശേരിൽ മാർ ദിവന്നാസ്യോസ് [Mar Dionyisus Vattasseril]. മലങ്കരസഭാ പിതാക്കന്മാർ (Fathers of Malankara Church) (in Malayalam).

• Malankara Orthodox Syrian Church
• Mar Thoma I
• Mar Thoma II
• Mar Thoma III
• Mar Thoma IV
• Mar Thoma V
• Mar Thoma VI (Dionysius I)
• Mar Thoma VII
• Mar Thoma VIII
• Mar Thoma IX
• Dionysius II
• Dionysius III
• Dionysius IV
• Athanasius
• Dionysius V
• Baselios Geevarghese II