The original owner of the land was the New River Company, in the parish of St James, Clerkenwell. On 20.11.1822, the Rev Handley of St James Church wrote to NRC and suggested to them that they include a church in one of the squares which they were constructing at that time. The Board of NRC met one day later, on 21.11. 1822 and granted land for a church.
The church was to be built ‘within six years’; the Grounds were to be enclosed ‘on all sides’ by ‘proper iron railings’; no burials were to be suffered in the Grounds; the grounds were to be kept ‘in perfect order and repair according to such regulations as may be proper for that purpose, without any expenses to the Company’; and that ‘in any Contract or Agreement … provisions .. be inserted .… for the accommodation of the Tenants and Occupiers of the surrounding estates’.
The church was dedicated to St Mark and the first vicar installed on January 1st 1828. A year later, In 1829, the land, now enclosed with iron railings, was laid out with ornamental gardens by Manfield and Durant Hidson. The lessees of properties in the Square met the cost of that work.
St Mark’s church was gutted in in the 1940s. Part of the north side of Myddelton Square was also destroyed and rebuilt in replica by the New River Company 1947/48.