[1] The Sempill family from the thirteenth century were hereditary bailiffs of the regality of Paisley and sheriffs of Renfrew under the Lord High Steward of Scotland.
In 1532 the King's armourer William Smithberde polished and sharpened the blades of eight two-handed swords given by Robert, other gifts were stockings and a tartan coat called a "galcot" in January 1533.
In April 1534, after Robert had reached his majority, James V exacted a financial penalty for his "non-entry" to the Sempill lands, punishing his father for non-payment.
Being a steadfast supporter of the queen regent against the Lords of the Congregation, he was described by Knox as "a man sold under sin, an enemy to God and to all godliness.
Sarlabous was asked in August 1560 to give him up but declined to do so until he received the command of Mary, Queen of Scots and Francis II of France.
Thomas Randolph shortly afterwards reported that Sempill had conveyed himself secretly out of Dunbar, and had retired to his own castle with twenty arquebusiers lent him by Sarlabous, and then that he had gone to France.
[14] A royal cannon with the insignia of James V of Scotland, probably used at this siege, was recovered from Castle Semple Loch in the 19th century and is now in the collection of Glasgow Museums.
On the 19 May he was, with the Earl of Glencairn, appointed Lieutenant of the Western parts, with special instructions to watch Dumbarton Castle, and prevent the entrance into it of provisions or reinforcements or fugitives.
[18] Calderwood states that he remained in Argyle for twelve months, but he was probably set at liberty in February 1571; for when the house of Paisley surrendered to the regent at that time, the lives of those within it were granted on this condition.
[19] Notwithstanding the utmost efforts of Glencairn and Sempill, the castle of Dumbarton continued to hold out, until, on 1 April 1571, its rock was scaled by his cousin Thomas Crawford of Jordanhill.