De Renzy, Sir Matthew (1577–1634), Irish planter, customs official, and Gaelic scholar, was born in Cullen (probably Cologne), Germany. His career reflects the possibilities open to continental immigrants in early seventeenth-century Ireland. Having spent some time as a cloth dealer in Antwerp, he moved to London and lived there as a merchant stranger in Bishopsgate, where his brother Lazarro (Lionel) also lived. A courier between Lord Cobham and Count Arenbergh, in November 1603 he testified at the trial of Sir Walter Ralegh (qv) and Cobham.
As a result of a commercial collapse in London in winter 1606, De Renzy fled via Scotland to Ireland, bringing, he later claimed, less than £5 with him. (His commercial failure in London dogged his Irish career, and as late as April 1634 De Renzy was still being pursued for debts incurred thirty years before.) He travelled widely in Ireland, and made himself known to the 4th earl of Thomond (qv) and the lord deputy, Arthur Chichester (qv). While in Co. Clare in 1607 he made contact with the Gaelic learned family of the Mac Bruaideadha, and started learning spoken and written Irish with them. A Mac Bruaideadha praise poem and biography, in his honour, survive.
Working as a land searcher, by 1613 he had acquired his own property, along the Shannon, in the lordship of Delvin Mac Coghlan in King's Co. (Offaly). From 1613 until c.1619 he lived in the midlands. His letters and notes reflect his concerns as an isolated planter living in a still-functioning Gaelic lordship, and his enmity with its loyalist lord, Sir John MacCoghlan. He drew on local knowledge, gleaned through his acquaintance with Irish, to establish full legal title to his holding.
In the reform of the Irish customs in 1619, the trio of William Massam (De Renzy's brother-in-law), John Pitt, and De Renzy became the agents of the farmers of the Irish customs, under the patronage of Lionel Cranfield, earl of Middlesex, lord treasurer of England. De Renzy moved to Dublin, where he had a house on Wood Quay, and supervised the customs there. The deaths of Massam and Pitt in 1622 increased his official duties: he took on the supervision of the lucrative tobacco farm, and became chief collector of the impost of wines, under James Hay, earl of Carlisle. De Renzy became the chief accountant of the farm of the Irish customs (until replaced briefly by Sir Edward Bagshaw in 1629), and succeeded Massam as Middlesex's Irish agent in 1623. He later became Irish agent of the earl of Carlisle, and, from 1626 to 1630, of the previous lord deputy, Oliver St John (qv), Viscount Grandison, lord high treasurer of Ireland. The lord deputy, Falkland (qv), conferred a knighthood on him in 1627. From April to June 1631 he served as the Irish agent of Philip Burlamachi in the purchase and export of wheat to London.
The 1619–20 midland plantations, for which De Renzy had campaigned, offered the prospect of further acquisitions. He increased his landholding in King's Co. through purchase and mortgage, as well as by plantation grant. In 1628 he became one of the first burgesses of the newly established plantation town of Banagher, King's Co.
He married twice after coming to Ireland: first (1608) Mary Adams of Dublin; his heir, Matthew (below), came from this marriage. His second wife was Ann, daughter of Richard Maypowder, an English servitor settled in Co. Roscommon. He died in Dublin, 29 August 1634, and a memorial plaque was erected by his son in St Mary's church, Athlone. His widow was living in their house on Wood Quay, Dublin, in the 1640s and 1650s; she died in Dublin, 20 August 1659, and was buried in St James's church there.
De Renzy claimed to have composed a grammar, dictionary, and chronicle in the Irish tongue within the space of three years, a claim noted by John Lynch (qv) in Cambrensis eversus (1662). None of these three works is known to have survived. According to the antiquary Roderick O'Flaherty (qv), however, this grammar was the work of De Renzy's tutor, Tadhg Dall Ó hUiginn (qv). The planter's surviving letters and notes contain topographical and genealogical material in Gaelic script, showing a knowledge of Irish perhaps unparalleled among those who settled in Ireland in the early modern period.
The career of his son and heir, Matthew De Renzy (c.1609–52), born in Dublin, reflects the close English involvements of the administrative class of the time. He had a brother, Francis, and two sisters. From 1626 to c.1632 he studied in England, both at a college and in the Inner Temple, London. In 1633 he became a member of King's Inns, Dublin, and married Mary, daughter of Sir John Moore and his wife Dame Dorothy, of Croghan castle, King's Co.
On his father's death in 1634, he inherited lands in King's Co. and Wexford; by 1635 he was established at Tinecrosse, King's Co. He continued his father's work as Irish agent of Lionel Cranfield (d. 1645), earl of Middlesex, and served on the commission for defective titles in the mid 1630s. As a result of a case in the court of castle chamber (by 1637), he was fined £2,000 (later reduced to £650), was put out of the commission of the peace, and was imprisoned. In the Irish parliament of 1640–41 he served as MP for an unidentified constituency, and he was allied through his marriage with several other MPs (Thomas Moore was his brother-in-law); in June–July 1641 he was a member of the committee of impeachment investigating the lord chancellor, Richard Bolton (qv), and others.
In January 1642 he claimed losses on properties in King's Co., Wexford, and Dublin city, together with monies disbursed in mortgages. By April 1642 he had moved to London, but his wife remained in Dublin. While in England he was in regular contact with the family of Lionel Cranfield, and on occasion stayed at Dorset House, the London home of the earls of Dorset (Cranfield's daughter Frances was married to the 5th earl of Dorset). He was agent to James, earl of Middlesex. In 1641 he had sold land in King's Co. to Sir Arthur Blundell, and Nicholas Loftus was involved in the transaction; in 1647 all three were in England, and made petitions to the house of lords about the deal. By 1650 he had a trunk containing the family papers, chiefly those of his father, brought to England, and deposited with the storehouse keeper in Chester; thereafter the collection became part of the records of the exchequer court of the county palatinate of Chester, perhaps as documents lodged in court in a case of debt; in this way the De Renzy MSS (PRO, SP 46/90–93) survived. While in England in 1650 he fathered a child with Anne Trelawney of Chester, and bequeathed to her his lands in Wexford. In August 1650 he went to Ireland; he had died by August 1652.
His brother Francis De Renzy (alias Keane) died in 1666; another Matthew De Renzy, who may have been the subject's son, died in 1664. By 1655 the latter was in possession of 1,200 acres in Scarwallish barony, north Wexford, which became the focus of the De Renzy estate in that county, and where the family was settled until the estate was sold under the encumbered estates act in 1864. Their seat was Clobemon Hall (built 1820). Thomas Furlong (qv) composed a long Gothic poem featuring a scion of the family as protagonist, The doom of Derenzie (London, 1829).