Letters exchanged between members of the Maurice and Owen families of Clenennau and Brogyntyn, and other correspondence from friends or associates in Wales and England, together with a number of important official documents deriving from county administration in Caernarfonshire during the Tudor and Stuart periods, 1485, 1573-1698. Many of the early letters and papers, 1580-1622, relate to the joint deputy lieutenancy in Caernarfonshire of Sir William Maurice and Sir John Wynn, showing their preoccupation with the raising and organisation of militia troops for the defence of Caernarfonshire and for despatch to Ireland. Other topics include Sir William Maurice's position as deputy vice-admiral of North Wales and the protracted civil lawsuits in which he was engaged. The collection also constitutes an important historical source for the conduct of the Civil War in North Wales. Items from that period primarily concern Sir John Owen and his brother, Col. William Owen, Royalist commanders at Conwy and Harlech respectively, and their subsequent treatment under the Commonwealth and Restoration, 1643-1666. Many of the letters from 1678 to 1698 reveal the life of Sir Robert Owen, his debts, estate business, cultural interests and attachment to the Jacobite cause, together with contemporary political news. Apart from individuals already mentioned, prominent correspondents include the Privy Council of Elizabeth I, mostly through Henry Herbert, President of the Council in the Marches of Wales, 1587-1600; Sir Henry Johnes of Abermarlais, 1605-1616; Ralph, Lord Eure, 1607-1617; members of the Brynker family, 1603-1681; the Wynn family of Glyn and Sylfaen, 1625-1697; the Anwyl family of Park, 1636-1693; Charles I, Prince Rupert and Prince Maurice, 1642-1647; Lord Byron, 1644-1648; John Williams, Archbishop of York, 1645-1646; George Twisleton, 1649-1660; the Godolphin family of Abertanat, 1658-1698; John Gadbury, 1679-1688; and Edward Lhuyd, 1696-1697.
