Abstract
Plaster was used to whitewash walls and wooden columns from the Achaemenid period, and the use of stucco continued to decorate buildings in the Parthian period. In the Sassanid period, plaster was used not only as a covering for walls, but also, due to the malleability of plaster, it was used to decorate mud and stone walls. During this period, plaster carving methods began to evolve and continued with greater variety in the Islamic period. On the northern coast of the Persian Gulf, a large number of plaster carvings from the Sassanid and early Islamic periods have been introduced by Whitehouse in the historical port of Siraf. During the archaeological investigation and identification of the historical port of Najirom, which is located ten kilometers west of the city of Dayer, Cultural materials on the surface of the site, including pottery fragments, glass, metal objects, coins, and plaster fragments, were studied. Among the cultural findings on the surface of this site, plaster fragments are of great importance for archaeological studies, historiography, and historical reconstruction of the historical port of Najirom due to their abundance and great diversity. In this field study, fragments of Sasanian-Early Islamic stucco carvings were collected on the slopes of hills overlooking the sea and a smaller number from stratigraphic trenches. In this research, the stucco carvings discovered from Najirom will be studied and the existing samples will be classified based on the type of stucco carvings. The variety and large number of stucco fragments, despite the lack of archaeological excavation, indicate the existence of large religious and public buildings, the prosperity of trade, and the construction of luxurious buildings within its urban fabric. The stucco carvings of the historical port of Najirom are comparable to those of Siraf in the Sassanid period and the first centuries after Islam.
Keywords: Plastering, Historical Port, Najirom, Persian Gulf, Sassanid, Early Islam.

Introduction
This historical waterway has long been of interest to power centers within Iran and foreign powers, and the most important trade routes, especially the Silk Road, passed through this region (Tofighian, 2018: 10). Dozens of historical ports on the northern coast of the Persian Gulf reflect the maritime trade, navigation, and shipping of Iranians throughout the ancient history of this land. As a link connecting Iran’s population and economic centers with civilizations on the same horizon in the Indian subcontinent, East Africa, and East Asia, historical ports have not only been places for the exchange of goods and merchandise, but also for the exchange of customs, traditions, religion, culture, art, and music. The presence of different religions and faiths such as Jews, Christians, Zoroastrians, and Shia and Sunni Muslims in the historical ports of the Persian Gulf is evidence of this claim (ibid.: 1402: 19).
The most important questions of this research are as follows: 1- What is the diversity of the Najirom gypsum arrays and what are the techniques used to make them? 2- Which of the parallel ancient sites on the coasts of the Persian Gulf and Iran are the Najirom gypsum arrays comparable in terms of culture? 3- What is the dating of the Najirom historical port gypsum arrays?
The most important hypotheses include the following: 1- Among the findings of the Najirom, there are a large number of broken pieces of plaster arrays, and the plaster arrays are of great variety, including geometric, Islamic, Samarra-type motifs, architectural elements, plant motifs, half-columns, inscriptions, functional and composite motifs.  2- The stucco decorations of Najirom are comparable to the historical ports of Siraf . 3- The stucco decorations of the historical port of Najirom date back to the late Sasanian period and the first half of the Islamic period.

Materials and Methods
In the archaeological survey and identification of Bandar Najirom in 2009 and 2013, pottery and other cultural materials such as fragments of plaster ornaments, coins, seals, beads, and metal objects were systematically collected and studied (Tofighian, 1993). The method of collecting information in this article is field research and library studies, and the research method is comparative studies with a descriptive-analytical approach to the findings from the archaeological investigation and identification of the historical port of Najirom. For this purpose, first, fragments of plaster arrays were separated, examined, and classified from among the mass of cultural materials. Then, for the purpose of comparison and relative chronology, plaster arrays from other historical ports of the Persian Gulf, including Siraf and Bardestan, were studied and compared 

Data
In archaeological surveys of the Najirom, countless pieces of plaster arrays were identified on the surface of the ruins of this historic site. 
1-Geometric motifs
The patterns of the plaster arrays of the historical port of Najirom include square, rectangular, circular, trapezoidal and triangular patterns that are repeatedly created in rectangular frames around the altar. 
2- Samarra-type plaster arrays, style C
Among the various plaster arrays, there is a type of plaster array called Samarra, which belongs to the Abbasid period and the first centuries after Islam. 
3- The role of architectural elements
Another part of the motifs of the Najirom plaster arrays is related to the role of architectural elements such as arches, arches, and corbels, which are drawn in the form of various arches, architectural niches, and decorative corbels. 
4-Plant motifs
Among the motifs of the Najirom plaster arrays, a larger number are related to plant motifs that are combined with other motifs. The motifs of coniferous trees, grape clusters, single leaves, repeated leaves, and the motifs of various three-petaled, four-petaled, five-petaled, and multi-petaled flowers decorate the surface of the Najirom plaster arrays.
5- Designs in the form of half-columns
One of the designs in the plaster arrays of the historical port of Najirom is the designs created in the form of decorative half-columns, where geometric, plant, and Islamic designs are created on the half-columns.
6-Inscription motifs
The large number of fragments of the Najirom plasterwork motifs in the form of inscriptions in Kufic script attracts attention. These inscriptions, which probably decorated the edge of the altar, include letters such as “m”, “la”, “hamd” and other letters.
7-Functional motifs 
Functional motifs are another type of arrangement found in the plasterwork discovered at the historic port of Nejirom. These motifs include pieces of overlapping arches in various dimensions and sizes, which were part of the functional decorations of entrances and niches.
8- Composite motifs
Most of the elaborate plasterwork arrays from the historic port of Najirom have composite motifs including plant, geometric, inscription and Islamic motifs. 

Discussion
In the archaeological investigation and identification of the historical port of Najirom and its 130-hectare area, broken pieces of plaster have attracted attention. These pieces of plaster arrays include geometric, Islamic, Samarra-type arrays, architectural elements, plant elements, half-columns, inscriptions, functional and composite motifs that have been created among various geometric frames.
The Najirom plaster arrays are mainly used to cover the surfaces of walls, niches, doorways, and mihrabs of mosques, and are combined to create repetitive patterns.
The methods of creating Najirom plaster arrays are in situ shaping and semi-embossed or low-embossed, and probably the plaster array motifs were created on the surfaces of the altar and other parts of the mosque using the Kasht-e-Bori technique. The frame method and the carving method are also other styles of creating Najirom plaster arrays. These patterns are mainly in the form of friezes or decorative strips, and a smaller number are made in the form of frames. It seems that most of the plaster arrays of Najirom belong to religious buildings and mosques, but some of the plaster arrays were separated from noble buildings and left on the surface of the site.

Conclusion
In the archaeological survey and identification of the historical port of Najirom and the stratigraphic survey program, 58 broken pieces of gypsum arrays were identified and studied. Among the broken pieces of gypsum arrays, 5 had geometric arrays, 4 had Islamic arrays, 3 are Samarra style arrays, 6 are architectural elements such as arches and corbels, 15 are plant arrays including various types of flowers, plants, and palm trees, 2 are half-columns decorated with geometric plant motifs, 12 have inscriptions in Kufic script and non-Kufic script, 5 have functional arrays such as tiered arches belonging to entrances and niches, and 6 have combined arrays including geometric, plant motifs, inscriptions, and other arrays. Broken pieces of plaster decorations were made from half-baked, half-pounded plaster mortar and adorned noble houses and public buildings such as mosques and altars. The plaster decorations of Najirom are comparable to the historical ports of Siraf and Bardastan in the Persian Gulf. Dating the plaster arrays of the historical port of Najirom is very difficult, given that they are mainly obtained from superficial surveys. In general, the plaster arrays of the historical port of Najirom belong to the late Sasanian period and the first half of the Islamic period. More accurate dating of the plaster arrays of Najirom requires archaeological excavation.