Robert had the same name as both his uncle and his grandfather. His uncle died before becoming Lord of Annandale, and therefore his father, William, inherited the title, becoming 3rd Lord of Annandale. Robert married ca. 1219 Isobel of Huntingdon, the second daughter of David of Scotland, 8th Earl of Huntingdon, by which marriage he acquired the manors of Writtle and Hatfield Broadoak, Essex in England.[4] They had 2 sons and a daughter:
Bernard de Brus of Exton, married firstly Alice de Beauchamp, daughter of William de Beauchamp of Elmley, [5]and married secondly Constance de Merston, widow of John de Morteyn;[5] was the father of Sir Bernard de Brus II.[6]
^Society of Antiquaries of Scotland Volume 14, page 345 (2020) The Society of Antiquaries of Scotland [data-set]. York: Archaeology Data Service [distributor] doi:10.5284/1000184
^The Scots peerage : founded on Wood's ed. of Sir Robert Douglas's Peerage of Scotland; containing an historical and genealogical account of the nobility of that kingdom by Paul, James Balfour, Sir, 1846-1931; page 430; https://archive.org/details/scotspeeragefoun02pauluoft/page/430/mode/1up
Duncan, A. A. M., ‘Brus , Robert (II) de, lord of Annandale (d. 1194?)’, in Oxford Dictionary of National Biography, Oxford University Press, 2004 accessed 14 Nov 2006
Miscellanea Genealogica et Heraldica, Volume 1. Hamilton, Adams, and Company. 1874.
Richardson, Douglas (2011). Royal Ancestry, Volume II. Douglas Richardson. ISBN9781731391681.