Frontiers of the Polish-Lithuanian Commonwealth, 1573–1674 is a facsimile-controlled research edition and English translation of selected Latin and French texts preserved in Bibliothèque nationale de France, Département des Manuscrits, Français 16936. The source is a composite political, ceremonial, and diplomatic miscellany rather than a single authored work. The materials selected for this edition illuminate the eastern and southeastern frontiers of the Polish-Lithuanian Commonwealth and the historical geography of territories now located largely within or adjacent to Ukraine. The edition centers on three documentary groups: Krzysztof Warszewicki's 1574 oration to Henry of Valois; a 1617 Polish royal response concerning Cossack and Tatar incursions and Polish-Ottoman treaty obligations; and the bilingual Latin-French election decree associated with the 1674 election of Jan III Sobieski. These sources contain references to Rus/Ruthenia, Volhynia, Kyiv, Bratslav, Podolia, Lviv, Khotyn, the Dnipro and Dniester river systems, Cossacks, Tatars, Ottoman relations, military administration, and seventeenth-century territorial titulature. Version 0.4 substantially extends the source control of the preceding edition. A 37-written-page facsimile-control corpus was established from Gallica images: three selected Warszewicki pages, eleven written pages of the 1617 Polish-Ottoman document, and all twenty-three pages of the Sobieski printed component. Direct image review corrected consequential HTR and editorial readings, including Boristenem vltra, Ciouia, Podhajeci, the paired French and Latin hydronyms Bog/Niester and Hypanis/Tyra, and other historical place and office forms. The review also discovered that the previously defined 1617 component had been truncated by one page; the recovered closing page supplies the formula post Pascham, creating an explicit internal dating conflict with a Latin rubric reading ante Pascha and a French summary reading après Pasques. The contradiction is preserved rather than harmonized. The edition deliberately separates six evidentiary layers: machine-generated HTR transcription, direct facsimile reading, editorial normalization, English translation, external-witness comparison, and historical interpretation. Modern geographic or biographical identifications are kept distinct from transmitted historical forms. External witnesses, including the Kórnik Warszewicki print, Peiresc manuscript materials, John Milton's 1674 English translation of the Sobieski election document, and Kórnik BK 385, are used as independent comparators rather than as substitutes for the controlling BnF witness. The accompanying evidentiary register and reproducibility materials document passage-level verification states, translation QC, external witnesses, source-text freezes, document genealogy, rejected readings, corrections, unresolved entities, and the revision history from Version 0.3 to Version 0.4. This is a research edition, not a claim to be a complete diplomatic or stemmatic critical edition of Français 16936. DOI: 10.5281/zenodo.22166720 Original English translations, editorial reconstructions, annotations, gazetteer, commentary, and other original contributions by Joshua D. Thoreson are licensed under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Historical source texts are not claimed as original copyright. CoMMA transcription data remain separately licensed under CC BY 4.0, and BnF/Gallica materials remain subject to their respective institutional reuse terms.