Possibly because of its minimal decoration--just a series of wavy incised lines found along the shoulders--this large green-glazed jar has often been attributed to the kilns at Kalong. However, the pale gray body distinguishes it from the Kalong wares, which were generally made of a pale, buff-colored clay. Shards with a gray body and a pale green glaze similar to those of this piece were found in 1979 at Phayao to the east of Kalong, and it has also been suggested that this jar is an example of Phayao ware. Identification of its provenance, however, is complicated by the fact that it was excavated from a 13th- or 14th-century stupa in the north-central city of Kamphaeng Phet, which is closer to the better known ceramic centers that produced Si Satchanalai wares. Moreover, ceramics made farther north in Thailand were intended primarily for local consumption, and few examples have been found in other regions of the country. When it was unearthed, this jar was filled with a large number of metal and terracotta votive tablets. It is possible that it was brought to Kamphaeng Phet from some other part of Thailand for a specific purpose.
The shape of this jar is similar to that of other examples from north and north-central Thailand. Funerary urns produced during the 11th and 12th centuries at kilns controlled by the Khmer empire of Cambodia provide one possible prototype for this widespread form.