[5] They had been deputed under Hyacinth of St. Vincent as Apostolic Commissar, by Pope Alexander VII to effect a reconciliation of Saint Thomas Christians of the Syro-Chaldaic Rite, who had seceded from the Archbishop Francis Garcia due to his over-stretched influence in the affairs of syro-chaldean eparchial province of India.

Sebastiani was consecrated Titular Bishop of Hierapolis on 15 December 1659 and sent back to Malabar, with the title of Vicar Apostolic and Administrator of the Archbishopric of Cranganore.

Nevertheless, it survived under the Indian Prelate Palliveettil Chandy (Alexander de Campo) whom Sebastiani had consecrated as his successor before he left Malabar in 1663.

By the brief "Multa Praeclara" of Pope Gregory XVI, dated 24 April 1838, the Sees of Cranganore and Cochin which at that time included also Quilon, were annexed to the Vicariate of Verapoly which thus came to comprise the whole of Malabar.

On 19 March 1887 the Catholics of the Syriac Rite were separated from those of the Latin Church and placed under an administrator, Marcelino Bernard of St. Teresa, who was consecrated co-adjutor to Archbishop Mellano.

By brief "Quod Jam Pridem" of Pope Leo XIII, dated 20 May 1887, the Syriac Rite Catholics were exempted from the jurisdiction of the Archdiocese of Verapoly and the two Vicariates of Trichur and Kottayam were erected for Syro Malabar Church (Malankara Chaldean Syrian church/St Thomas Christians/ Nazranis) with Adolpus E. Medlycott and Charles Lavigne as their Vicars Apostolic.