This article presents a new manuscript containing previously unknown witnesses to seven poems by Katherine Philips. In the 1680s Robert Mathewes, a young gentleman from rural Shropshire, kept a commonplace book, now held at Staffordshire Record Office, into which he entered a small but varied selection of Philips’s verse. An examination of these transcriptions, focusing on the changes he made to the originals, allows us to see Mathewes not only as a reader but as an editor of Katherine Philips’s poetry. His interest in Philips’s works is compared to the Duke of Monmouth’s contemporaneous engagement with the poet in his pocket book, which offers an unexpected complementary reading of ‘A Country-life’. Mathewes’s commonplace book also contains pedagogical exercises, evidence of the educational programme that he was following, an attempt at poetic composition, and a catalogue of his library, allowing insight into a young man’s scholarly life. An annotated transcription of Mathewes’s book catalogues and a first and last line index and collation of the Philips poems are included as appendices to the article.