Dennistoun was born in
Dumbartonshire in 1803, the eldest son of Mary Ramsay, daughter of
George Oswald of
Auchencruive and James Dennistoun (died 1 June 1834). After receiving his education at the universities of
Edinburgh and
Glasgow, he became a member of the
Faculty of Advocates in 1824. During a
continental tour in 1825 and 1826, in which his companions were
Mark Napier,
Hamilton Gray, and
Sir Charles Fergusson, the
art and
literature of Italy first engaged Dennistoun's attention. After his father's death he sold the family estate on the shores of the
River Clyde and purchased the farm of Dennistoun in
Renfrewshire, the centre of the original possessions of his family in that county. In 1833 "James Dennistoun, advocate" is listed as living at 1 Albyn Place, a huge house at the north-east of Edinburgh's
First New Town on the edge of the Moray Estate. In 1836 he again went abroad, and spent 12 years away from home, chiefly devoting himself to literary research and art. The winter generally found him in
Rome, while the summers were given to journeys in
Italy and Germany. He formed a collection of early Italian pictures, drawings, and mediæval antiquities, with which he adorned his house in George Street,
Edinburgh, his permanent home from 1847. He was a magistrate and deputy-lieutenant for the
county of Renfrew, and became a member of most of the societies formed for collecting materials for illustrating the
history of Scotland. In 1835 he married in Isabella Katharina, eldest daughter of the
Honorable James Wolfe Murray, Lord Cringletie. He died at 119 George Street,
Edinburgh on 13 February 1855, aged 52. Most of Dennistoun's collection of pictures, drawings, and antiquities was sold at
Christie & Manson's on 14 June 1855. ==Works==