Šams al-Dīn, ancient Mounēsis (Μουν[ῆ]σις / Μωνῆσις), is a large Late Roman settlement situated in the southern part of Kharga Oasis, approximately 5 km north of Bārīs and 18 km north-west of Dūš (Kysis). Rather than lying on a single caravan route, the settlement occupied a nodal position at the intersection of routes connecting southern Kharga with the northern part of the oasis, the Nile Valley to the east and Dakhla Oasis to the west. The archaeological area extends approximately 1,300 m north-south by 750 m east–west, while the visible remains of the main settlement occupy some 0.975 km². The principal built-up area is divided by a major east–west street. To its north lies a group of structures tentatively identified as a military compound and associated stabling, while most of the residential quarter extends to the south. At least nine probable domestic units have been identified east of the principal north–south circulation axis. The two principal religious buildings, a mud-brick temple and the church complex, occupy the western sector of the settlement. A large structure in the south-east, probably several storeys high, may have served for storage and could correspond to the φρούριον mentioned in a Greek ostracon found in 2021. The settlement lies between the wells of ʿAyn Dawūd to the north and ʿAyn Šams al-Dīn to the south; a smaller settlement area occurs south of the latter, while a cemetery has been identified south-west of the main settlement.

The temple, situated approximately 40 m north of the church, is an east-west-oriented mud-brick building measuring c. 27 × 10 m within an enclosure measuring approximately 48 × 19 m. Excavation has demonstrated that the monument was systematically dismantled, generally leaving only the foundations and the lowest two or three courses of its walls. Nine clay disks, apparently votive or offering objects, constitute virtually the only surviving evidence for its cultic use, and the divinity or divinities worshipped there remain unknown. Radiocarbon determinations associated with the construction of the temple produce a broad modelled range of 251-350 CE (2σ). When considered together with the ceramic evidence and the wider history of temple construction in the Great Oasis, however, a date in the second half of the third century constitutes the present working hypothesis. The date and circumstances of its abandonment remain substantially less secure. Its careful dismantling preceded secondary occupation of the area in the second half of the fourth century, but the available chronological evidence is insufficient to demonstrate that its demolition was directly connected with the construction of the nearby church.

The church is a three-aisled basilica whose nave is divided by two rows of three columns, with an additional western column producing a return aisle. It has no semicircular apse; instead, the eastern end contains a raised rectangular sanctuary, approached by two steps, with a separate space to the south. Other liturgical fittings include wall seating, a lectern and traces of a chancel. Photographs taken during the 1976 excavation also record a painted decorative scheme of horizontal red lines, now lost through erosion of the plaster. Investigation of the standing masonry has fundamentally modified the earlier understanding of the building: the church was not erected ex novo but resulted from a complex adaptation of a pre-existing domestic fabric. Walls belonging to several earlier structures were incorporated into the new building, while others were dismantled in order to create the nave and sanctuary.

The absolute chronology of the church has likewise been considerably refined. Bayesian modelling of three accepted radiocarbon determinations associated with its construction places this event within 310-382 CE at 2σ and 319-359 CE at 1σ, with the medians of the individual modelled determinations clustering around 339-341 CE. The highest probability therefore lies around the middle of the fourth century. The construction and subsequent development of the church progressively reorganised the surrounding domestic fabric. The complex eventually included the vestibule, corridors, the kathesterion, rooms giving access to the roof, and other ancillary spaces. The portico west of the church (R6), which was added to the original building, contained a centrally placed semi-sunken mud-brick installation interpreted as a baptismal font and is therefore provisionally identified as a baptistery.

Excavations immediately north of the church in 2022 further clarified the history of this sector. Contrary to the initial hypothesis that the church simply blocked a pre-existing open processional route leading south from the temple, the church was inserted into an already structured domestic environment, selectively modifying earlier patterns of circulation. Most of the walls now subdividing the area north of the church post-date its construction. Subsequent phases involved repeated architectural reorganisation and increasingly modest uses of the area, including storage, pastoral and domestic activities, before the final collapse of parts of the built complex.

The written evidence remains particularly important for understanding the settlement. The 1976 excavations recorded 67 Greek graffiti and six ostraca, many of them associated with soldiers belonging to Nile Valley units stationed in Kharga. The military character of part of the settlement has received further support from a Greek ostracon discovered in 2022, which mentions the cornicularis Hōrigenēs. Another ostracon found in R17 during the 2021 excavations, datable through prosopographical connections to 363/364-380/381 CE, provides a terminus for the final occupation of rooms R16-R17. The wooden tablet discovered in the sanctuary in 1976, originally assigned to the third century by Wagner, should no longer be cited uncritically as evidence for that date, since its possible connection with a fourth-century officer has called the earlier dating into question.