The Flemings take their name from the Flanders region. The earliest record of the Flemings of Biggar was around 1160 when one Baldwin Fleming was granted land and became a powerful baron of the time. It is probably Baldwin who first attained the land and barony of Garscadden in the reign of Malcolm IV, as part of the continuation of the feudal system started by David I. By the time of Alexander II, the Flemings were granted Auchentorlie in 1226, and Dalnottar in 1248 increasing their holdings in the Kilpatrick parish. William Fleming was the Constable of Dumbarton Castle in 1288 and Custumar [Customs Officer] of Dumbarton in 1292, presenting the accounts of the Sheriff of Dumbarton, also the Earl of Fife, at Linlithgow in 1289.
Although there was in total, 9 Flemings who signed the Ragman's Roll - swearing fealty to Edward Longshanks - the Flemings were supporters of Robert the Bruce and the family motto came from a legend involving the rise of Bruce. It was probably the same previously mentioned William Fleming that signed the Roll in fealty to the English King Edward I for his lands in Barochan, Renfrewshire, that later received remission of his rents due for the lands of Kirkmichael near Dumbarton sometime after the battle of Bannockburn. The Garscadden laird, Malcolm Fleming obtained Kirkintilloch as part of the forfeiture of the Comyn's estate when Bruce was king. A keeper of Dumbarton Castle, he was made the Earl of Wigton in 1341 by David II.
The Dumbarton Castle appointment fell to John Dennistoun in 1359, Malcolm's son-in-law. (The Dennistoun family were originally from Danzielstoun near Kilmacolm in Ayrshire and it from their descendents that the Glasgow suburb of Dennistoun is so named.) It then passed to Malcolm Fleming's nephew, another Malcolm Fleming in 1364. The son of the Earl of Wigtown, Patrick Fleming, exchanged Garscadden for the lands of Board with Sir Robert Erskine in 1369. This Sir Robert Erskine also became keeper of Dumbarton Castle for a time. On the succession of Robert II, John Dennistoun was confirmed again as keeper, no doubt as the king was married to Dennistoun's niece, Elizabeth Mure.
Another Malcolm, Sir Malcolm of Biggar and Cumbernauld was one of the hostages for the release of James I. He was beheaded on the 24th November 1440, being one of the Douglas party executed by the Lord High Treasurer Sir Alexander Livingston when dining with the young James II. Later however James II returned his lands to his son, Sir Robert, and made him a Lord of parliament.
The 4th Lord Fleming accompanied Queen Mary to France in 1548, and took ill at Dieppe supposedly by poison.