This is a new critical and commented edition of the Planctus Magistrae Doloris, a vernacular old Veronese prose version of a Planctus Mariae that was copied in the second half of the 14th century. While a first transcription was published in 1891 by Gustav Oehlert, the current editor has succeeded in identifying the Latin version the vernacular text was drawn from, allowing him to clarify some difficult passages. Moreover, the author has established a stemma codicum of the three manuscripts that transmit the Latin text, illuminating the branch of the tradition on which the vernacular depends. This edition also contains a detailed linguistic commentary and glossary.