Fleming, Thomas (d. 1434/5), Lord Slane, Anglo-Irish baron, son of Simon Fleming (d. 1370), baron of Slane, and Cecily, daughter of Thomas Champernoune of Modbury, Devon. When Simon Fleming died on 13 September 1370, his lands were taken into the king's hand, since Thomas was still a minor. On 9 October 1372 Edward III sold to Sir Robert Preston (qv), 1st Lord Gormanston, the wardship of Thomas and custody of the Fleming lands; Sir Robert ensured that relations between the houses of Slane and Gormanston remained close by marrying his daughter Elizabeth Preston (d. in or after 1403) to his ward.
On 17 October 1380 Fleming gained his majority and seisin of his father's manor of Duleek, Co. Meath, beginning his career as an important local magnate in Meath. One of the major threats to his secure enjoyment of his lands were the Irish of west Meath and Offaly. Slane obtained permission to treat with them on 20 February 1386. His rising importance was demonstrated by his appointment on 8 August 1388 as a commissioner to supervise the local guardians of the peace, and he sat in the Irish parliament of 1394–5. Thereafter he seems to have gone to England, returning to Ireland to serve with Edward, earl of Rutland and Cork; he was knighted before 2 July 1396 and sat in the parliament of 1399–1400.
After the fall of Richard II (qv) in 1399, Slane fell out with the new Lancastrian government, as an order for his arrest, with his wife and son, was issued on 14 June 1401. But he managed to rehabilitate himself, was pardoned on 14 June 1403, and resumed possession of most of his lands by 1410. His first wife died in or shortly after 1403, and Slane took as his second wife Katherine Butler (d. in or after 1435), reputedly the natural daughter of James Butler (qv) (d. 1405), 3rd earl of Ormond. He received a further sign of favour in the form of a royal licence (dated 16 February 1412) to hold a weekly market and an annual fair at Drumconrath, Co. Meath. The emergence of Murchadh O'Connor Faly (qv) (d. 1421) and his son An Calbhach Mór O'Connor Faly (qv) (d. 1458), gave Slane much to fear from the Irish of Offaly. On 10 May 1414 disaster struck when the O'Connors Faly routed the English of Meath, capturing Slane's son Christopher Fleming. After obtaining Christopher's release, it seems that Slane travelled to England in late 1415 to visit his lands in Devon. Little is known of him thereafter. He died in 1434 or 1435 and may have been buried beside his first wife at St Mary's friary in Youghal, Co. Cork (his second wife chose also to be buried there). Christopher Fleming was knighted on 12 July 1425.