The period of fifty years, over which the present volume extends, may be divided into two portions, the first embracing the reigns of Robert I. and Edward II., which nearly coincide; the second, those of David II., from 1329 till his return from captivity in 1357, and of Edward III., from 1327, for the first thirty years of his long tenure of the throne.<br><br>Besides the Chronicon de Lanercost, the Gesta Annalia of Fordun, and works of that class, there are two other authorities of the highest value for the period embraced in this volume. These are the Scala Cronica of Sir Thomas Gray of Heton, and the Metrical History of the Brus, by Archdeacon John Barbour. The statements in both of these have been tested by many entries in this volume, the bearing of which attentive readers will not fail to discover for themselves. Barbour abounds in graphic pictures of his hero's career, and of those who served with or against the King of Scots. In these details he is almost always correct, with occasional errors in names. Writing as he did at a long interval of time, about half a century after King Robert's death, the arrangement of his story is often imperfect, the succession of events transposed, and wrong dates given, capable, however, of being corrected by other authority, and detracting little from the real historical value of The Brus. On the other hand, Sir Thomas Gray, who compiled or at least began his chronicle while a prisoner in Edinburgh castle about 1355, was an actor in many of the events which he describes during the reign of Edward III.