The Brent Memorial Brass at St. Mary's Church, Ilmington in Warwickshire, says this man came "out of Somersetshire about the yeare 1487 by the concealed name of John Buston". Peerage records and records of Margery Colchester lead to the determination that his true name was Robert Brent.

The Brent Family history in "De Bow's Review" records: "The aforsaid Robert, son of Robert by Margaret, in 1487, came to Stoke near Campden in Gloucestershire and there lived concealed by the name of John Buston, and married (Margery), daughter of George Colchester, Lord of Stoke and Admington, aforsaid." ("De Bow's Review", as quoted by C.H. Brent, p. 35) The reason for his leaving Somersetshire using an assumed name remains unclear.

It was a tumultuous period in English history, with Henry VII having overthrown Richard III in 1485, after Richard had overthrown his own nephew, Edward V, only a few years before. In 1487, a rebellion against Henry broke out, organized around a man pretending to be the Earl of Warwick, another nephew of Richard III. The false Warwick was defeated in June of that year. Henry VII's position on the throne remained tenuous through the remainder of the 15th century.

Based on the timing, it seems the most probable conclusion that Robert Brent, alias John Buston, fled Cossington, Somersetshire, in fear of the new crackdowns that followed Henry VII's coming to power. There is no way of knowing if Robert had sided with one of the rebellions, or was too closely linked to the cause of Richard III, but the fact that the rest of the Brent family remained in Somersetshire apparently unmolested suggests that Robert fled both for his own safety and to avoid endangering his family's position. His son, William, is referred to in the will (1547) of Richard Colchester, Robert's brother-in-law, as "William Busten otherwise called Brent". Presumably, Robert maintained his alias at least until the death of Henry VII in 1509, and it seems that he was still using it to some degree when William was born.

Even after Robert felt it was safe to resume the Brent name, many in and around Stoke would have continued to think of him primarily by the name Buston.