He met in Italy the Florentine architect Alessandro Galilei, who was working from afar on a vast grandiose mansion near Dublin – Castletown.
He spent some time in Norfolk in the 1720s, where he carried out a number of architectural commissions for local families including for the original iteration of Shadwell Court (1727-29) along with his distant relative, the amateur architect John Buxton.
[2] By 1724, Pearce had returned to Ireland to become a practising architect in Dublin, It would appear that as the only Irish architect, at the time, to have studied in Italy, his classical concepts were to win him instant recognition, his architectural success seems to have been almost instantaneous; no doubt helped by his contacts and position in Irish society and even more undoubtedly by his association with William Conolly and Castletown.
The mansion was commissioned by William Conolly (1662–1729), a self-made man who had risen from humble origins through astute property dealings to become one of the wealthiest and influential men in Ireland.
The original plans were drawn by Alessandro Galilei circa 1718, the new mansion was intended to reflect Conolly's political power as Lord Justice of Ireland.
Galilei was certainly responsible for devising the overall scheme of a principal centre mansion, flanked by colonnades leading to two service wings, in the true Palladian manner.
In this layout of state rooms, hall and staircase Castletown is similar to Blenheim Palace, which Pearce had studied while a student of Vanbrugh.
The composition is a hybrid between the grandest of the Veneto's villas and a slightly exalted farmhouse, which ironically was the very intention of Palladio's original designs 200 years previously.
This granite monument, over 100 feet high, contains in its base a large vaulted hall from which rises a staircase leading to a viewing platform.
In 1727, Pearce was elected Member of Parliament in the Irish House of Commons for the Ratoath in County Meath, assisted by his patron Speaker Conolly, for whom he was continuously working at Castletown.
The Irish Government had decided in that same year to replace their existing meeting place at Chichester House, College Green, Dublin with a new purpose-built parliament building.
The foundation stone of the new Parliament building was laid in 1729, the Palladian design was, as intended, awe inspiring with a huge colonnade facing onto College Green.
The public gallery here could hold up to 700 spectators, symbolising true open government; the smaller but still exquisite House of Lords survives, along with its central arcade and pediment.
The building at the beginning of the 19th century was taken over by the Bank of Ireland, substantial alterations have been made since, including a large extension by Gandon and Johnson.
The result was a large unostentatious red brick Palladian mansion, on two principal floors, the hipped roof hidden by a brick pediment, the main façade seven bays long had at its centre a three bayed projection, the only ornament was dressed stone double strapping indicating the ground and first floor division.
Pearce also designed smaller and more modest town houses for the wealthy and aristocratic of Dublin; two examples of his work survive in Henrietta Street (illustrated above right).
Tragically it was to be a short period, within weeks of receiving the freedom of Dublin, he was struck down with an abscess and died of septicaemia 16 November 1733 at his home, The Grove, Stillorgan, aged just 34.