The chapel on Kőszeg Calvary, built in 1715, is the earliest solid religious building in this location and was constructed even before the present Calvary Church. It was built next to the wooden cross erected in 1686 and is associated with the intense religious practice that followed the plague of 1712, which prompted numerous vows and donations. No builder by name is known; the construction is generally attributed to the Jesuit community, which had a spiritual influence on Calvary and later also initiated the construction of the church. The small, single-nave Baroque chapel has a rectangular floor plan, white plastered walls, and a steep tiled gable roof with a slender ridge turret and cross. Above the portal is a plaque bearing the date 1715. The entrance is accessed via a short staircase with side balustrades and is flanked by two small Baroque figures; a side window provides sparse light. According to local tradition, the chapel is dedicated to St. Donatus.