The Erskine family correspondence is an extraordinary archival treasure trove, largely overlooked in accounts of the Early Modern period. This thesis will unlock this outstanding cache of le@ers and thus cover new, important, archival ground. Its substanGve findings will provide fresh insight into language and society at a key period of Sco2sh history (the ReformaGon, Covenanters, Civil War) and highlight the life and disGncGve epistolary voice of the remarkable countess of Mar. It will emphasise the implicaGons of editorial decision-making for language-idenGty formaGon today, as we look towards a future where more Sco2sh archives are made accessible.