Shaen, Sir James (a.1629–1695), 1st baronet, revenue farmer, and politician, was the eldest son and heir of either Patrick or Francis Shaen, but his origins are otherwise obscure. He married, in 1650, Frances, fifth daughter of George Fitzgerald (qv), 16th earl of Kildare, and his wife, Joan, daughter of Richard Boyle, 1st earl of Cork (qv). James Shaen's wife was thus a first cousin of Richard Jones (qv), later earl of Ranelagh, the great rival of his later career. Shaen held several appointments under the Cromwellian regime: in 1654 he was a member of the commission for setting out lands in Connacht and Clare for transported Irish; in 1655 he was sheriff of Co. Longford and Co. Westmeath; and in 1656 was cornet of a troop of horse in Ulster.
Shaen continued to enjoy offices and honours after the restoration of Charles II. In October 1660 he was made cessor, collector, and receiver general of Leinster for life; in December 1660 he was knighted; in March 1661 he became registrar of the first court of claims; and in September 1661 he was secretary to the lords justices of Ireland. He sat in the Irish house of commons for Clonmel, 1661–6, but the court rather than parliament was to be his preferred theatre of action. In late 1662 the Irish government faced a severe shortfall in revenue and the lord lieutenant, the duke of Ormond (qv), sent Shaen to London in December to seek a subvention of £60,000 from the English government. Shaen's mission failed, for Charles II and his ministers were preoccupied by their own financial problems. Shaen, however, appears to have found his sojourn at court useful, becoming known to the king and courtiers, and proposing to raise a loan for Charles II. He was created a baronet in February 1663, and became one of the original fellows of the Royal Society in May 1663.
Shaen became more prominent in the 1670s. When the lord lieutenant, Lord Berkeley (qv), wished to counter the hostile influence of Ranelagh in 1671 he engaged the support of Shaen, who was then at the English court. Shaen was subsequently involved in a series of proposed Irish revenue farms. In December 1673, with William Muschamp (d. 1683) and Robert Gorges (qv), he negotiated inconclusively with the English brothers who had farmed Irish revenues since the 1660s, James and John Forth. He then made several attempts, in opposition to the Forths, to obtain the farm of the revenue; eventually in December 1675, Shaen, with Sir William Petty (qv) and Muschamp, was awarded the farm in succession to Ranelagh.
An intense struggle for control of the Irish revenue ensued between 1677 and 1679, in which Ranelagh and the earl of Danby were pitted against Shaen, who was supported by Laurence Hyde (qv), earl of Rochester, and successive lords lieutenant, Essex (qv) and Ormond. Ranelagh failed to dislodge Shaen, whose management of the revenue, like Ranelagh's own, gave rise to much dissatisfaction and suspicions of corruption. In 1679 and 1680 the lord lieutenant, Ormond, oversaw preparations for a proposed Irish parliament. Shaen, fearing parliamentary attack, intrigued against it, criticising Ormond's proposed revenue legislation and offering the prospect of more lucrative schemes of his own. In 1682, however, Shaen, who had bid too high in order to win the revenue farm, began to renege on his commitments. The collapse of his farm in 1682, amid disarray and disputed accounts, effectively marked the end of a system of tax which he and Ranelagh had brought into discredit.
Shaen, who had also been made surveyor general for life in 1667, largely disappeared from view after 1683, though he sat in the Irish house of commons, for Baltinglass, in 1692 and 1695. He died 13 December 1695, and was succeeded in his estates and baronetcy by his only child, Arthur (p. 1650–1725), who sat in the Irish house of commons for Lismore in every parliament from 1692 till his death. Arthur owned one of the earliest greenhouses in the country, at Kilmore, Co. Roscommon, near Athlone. He was a member of the Dublin Philosophical Society, and was made honorary LLD of TCD in 1709. He died 24 June 1725 at Kilmore, when the baronetcy became extinct. An air by Turlough Carolan (qv) commemorates Sir Arthur.