Archaeological oversight had been set up at the castle in Malbork for the years 2021-2023, for purposes of reconstructing so-called Buildings C & D along the west line of Outer Castle development. The oversight coincided with the 2023 opening season of archaeological surveys forming part of a project intended to analyse the Outer Castle in greater detail. These activities involved a number of discoveries and observations, all of which a source of new data required to reconstruct and convert this part of the castle. It turned out that a quay dating back to the fourth quarter of the 13th century had existed on the banks of River Młynówka prior to Outer Castle development, a natural water reservoir located east of what would become the line of edifices; the reservoir would be used as a pond, which had ultimately disappeared by mid-18th century. Individual stages of local development were successfully confirmed, the investment progressing from north to south, Saint Lawrence’s Church the final structure. In general terms, Outer Castle development can be dated to the second quarter of the 14th century. Methods applied in laying foundations for Outer Castle walls, and for cellared and non-cellared edifices, were duly identified. A malt kiln dated to the 14th century and 17th-century interior conversions were found in the north building. The scope of 14th-century filling earthworks on either side of the line of edifices was examined as well. The discovery of wall relics surrounding the line of yards to the east of the development allowed their width to be established at approximately 23.5 m. Smaller structures had been erected in aforesaid yards, one of which captured east of a building which used to house an infirmary in the Middle Ages, and a brewery in early modern times. It would ultimately turn out that the yard structure formed part of the original 14th-century settlement. An area near the church served as a graveyard rather than a regular yard, the morgue within – known from early modern accounts and plans, its walls also found – turning out to be mediaeval as well. The archaeological oversight allowed multiple wall relics in Outer Castle infrastructural excavations to be documented. Sections of Gothic walls of a gate complex opening up onto the River Nogat from the Outer Castle, and 18th- and 19th-century housing foundations, were found west of the bridge on the River Młynówka. Foundations of two 19th-century lavatory outbuildings were discovered in the edifice line east section. In addition, foundations of a 19th-century fortified wall were found in the north-eastern section of the Middle Castle’s moat.