His father, Robert Traill of Greyfriars, was well known, being born in 1603, the son of Colonel James Trail, of Killcleary, Ireland, Gentleman of the Privy Chamber to Henry, Prince of Wales, and grandson of the Laird of Blebo, and Matilda Melvill of Carnbee.

[6] Robert Traill's early education was carefully superintended by his father, and at the university of Edinburgh he distinguished himself both in the literary and theological classes.

[8] He was for some time tutor or chaplain in the family of Scot of Scotstarvet, and was afterwards much with John Welsh, the minister of Irongray, who was the first to hold ‘armed conventicles.’ He became a lifelong friend of William Guthrie of Fenwick, author of "The Christian's Great Interest".

[9] In 1666, he was obliged to lurk for some time, together with his mother and elder brother; because some copies of a book, intitled, "An apologetic relation, &c", which the privy council had ordered to be publicly burnt, were found in Mrs Traill's house.

[11] There he continued his theological studies, and assisted Nethenius, professor at Utrecht, in preparing for the press Samuel Rutherford's ‘Examen Arminianismi.’ In 1669 he was in London, and in 1670 was ordained to a presbyterian charge at Cranbrook in Kent.

He admitted that he had preached in private houses, but, refusing to purge himself by oath from the charge of taking part in holding conventicles, he was sent as a prisoner to the Bass Rock in the Firth of Forth.

The sentence of in July 1677 read: "Forasmuch as the Lords of his Majesty's Privy Council, finding by the Report of the Committee anent Public Affairs, that Mr Robert Traill, son of the deceased Mr Robert Traill, against whom letters of intercommuning are direct, and who is excepted forth of his Majesty's gracious act of indemnity for his being in the rebellion in the year 1666, being apprehended within the city of Edinburgh, and brought before the said Committee, and examined if since his last coming to this kingdom he had kept any house or field conventicles, did acknowledge he had kept house conventicles, but said he left it to proof as to field conventicles; and the verity thereof being referred to his own oath he refused to depone; and confessed he had conversed with Mr John Welsh on the borders, and had assisted him at preaching in the fields, but especially upon the borders of the English side, where he said he had stayed for the most part since he came last to Scotland; and that he had been in and about Edinburgh since the end of May last; and that being interrogated by what authority he took upon him to preach, he declared that, in the year 1670, he was ordained minister by some Presbyterian ministers at London; and acknowledged that he had seen the printed act of indemnity out of which his name is excepted: The said Lords do ordain the said Mr Robert Traill to be sent prisoner to the Bass, until the Council consider what further shall be done with him.

"On the same day, "The Lords of his Majesty's Privy Council do grant warrant and order to the Lord Marquis of Athole, to command such a party of horse as he shall think fit to transport the person of Mr Robert Traill from the Tolbooth of Edinburgh unto the Isle of the Bass, to remain prisoner there.