Oldest Portuguese Churches of Kolkata, India - a short note,

Cathedral of the Most Holy Rosary; or, Portuguese Church, Murgihata, Calcutta, 1826.puronokolkata.com
Since more Europeans arrived in large numbers soon after the mercantile activities of Portuguese settlers, the European community began to grow  as time went by. When the British East India company operations had begun to  expand  more and more people made a beeline to that region. Later the British  formed a settlement and built a fort to protect their mercantile activities and their merchandise.  Hence, among the British colonies, Kolkata has the unique distinction of having so many historical and colonial buildings that bear testimony to their past glory and legacy.  However, the presence of Portuguese merchants to this part of Bengal is recorded far before the coming of British merchants. Portuguese settlers built the oldest churches here.

Cathedral of the Most Holy Rosary; or, Portuguese Church, Murgihata, Calcutta, 1826:

Historical evidences suggest that the Portuguese from Hugli (Hoogley),  settled here long before the arrival of the British East India company and later founding of Calcutta by Charnock, a British official in 1690. Because of growing Christian community in this are,  church services were needed. So Portuguese built a chapel that were   attended by Augustinian priests. The chapel was replaced by the impressive  church dedicated to Our Blessed Lady of the Rosary and the same place of worship is  is used today as the cathedral, commonly  referred to  as the Portuguese Church, and the street on which the Church is located was named Portuguese Church Street until recently, in the area of Murgihata adjacent to Lalbazar. The main Church of the Padroado in Kolkata till 1834, became the first parish Church of the newly erected Vicariate Apostolic of Bengal and the Salesians, took the control  from the Jesuits in 1921 and later handed it over to the Diocesan Clergy in 1972. The Cathedral Annexe was built in 1979. 

credit: Colored aqua tint by James Baillie Fraser, Plate No.17 from ‘Views of Calcutta and its Environs’. It may be noted that the location as indicated on the Plate, is not Lollbazaar (Lalbazar) but Mughihatta (Murgihata).
Portuguese Church, Dharmatala Street, Calcutta, 1848:
Portuguese Church, Dharmatala Street, Calcutta, 1848.puronokolkata.com/
Portuguese Church, Dharmatala Street, Calcutta, 1848
Originally a Roman Catholic Church for the Portuguese community in Calcutta, with the passing of the Catholic Emancipation Act  in 1829,  the church was built by Mrs Pascoa da Souza, a member of the prominent Portuguese family, the Barrettos, between in 1832 and 1834. It was erected behind Dharamtola Bazaar on Dhurrumtollah (Dharamtola) Street at the center of British Calcutta.

Credit: This colored lithograph, dated 1848, is taken from plate 7 of Sir Charles D’Oyly’s ‘ Views of Calcutta and its environs’.