Introduction
Despite the location of the Tarrom region between the well-known cities of Zanjan, Ardabil, Qazvin, and Rasht, it has received less attention in historical texts compared to the aforementioned regions. The aim of this study, based on a field survey, is to investigate the identification, quality, and quantity of Islamic-era settlements in the study area and to analyze some relevant information from historical texts. The main questions addressed in this study are as follows: 1. What was the quality and quantity of Islamic-era settlements in the villages of Abbar and Darram? 2. What insights can be gained from comparing historical texts and archaeological evidence regarding the study area during the Islamic period? 3. Based on the survey data, which site or sites in the study area can be identified as the main centers in the basin of the Abbar and Darram villages during the Islamic period?
It is assumed that the study area housed various settlements during the Islamic period.

Research Method
This research was carried out in two parts: field and library studies. In the field section, the ancient sites of the study area were examined, and cultural materials, mainly including pottery fragments, were collected. In the library section, the Islamic pottery of the sites in the study area was typified, and the distribution of the sites in the region was examined and evaluated using common methods such as GIS. Additionally, special attention was paid to historical and geographical texts of the Islamic period in the library studies section.

Research Background
So far, very few archaeological studies have been conducted in the study area at Tarrom Olya County, the most important of which was the first season of the survey of Tarrom County under the supervision of A. Najafi in 2007, as a result of which 96 ancient sites related to different periods were identified (Najafi, 2007). The present study was conducted based on the results of this survey.

Discussion
- Historical and archaeological evidence of the study area in the early Islamic era
Historical sources indicate that during the Musafirid rule in the fourth century AH, the Tarrom region, particularly the fortress of Samiran, experienced a period of development and prosperity as mentioned in Naser Khosrow Qobadiani’s travelogue. Subsequently, the Tarrom region became a battleground between the Ismailis and Seljuks and a target for conquest by Mongol, Ilkhanid, and Timurid rulers seeking to control Gilan. Notably, Tughrol Beig visited Tarrom Castle in 454 AH and demanded a substantial sum from its ruler (Ibn Athir, 1991: vol. 22: 375). Various castles and locations in Tarrom, such as Andjan, Rustamkuyeh, Sheruz, Kufal, Harkam, Samiran, and Qalat, are mentioned in historical sources from this period (Hamawi, 1995; al-Baghdadi, 1412). Archaeological findings from eight sites in the Abbar and Darram districts, including Tape Las, Sharfan Darreh, Ghaybullah, Torobar, Tape Chenar, Mine Bala, Sibisun, and Dam, contain pottery dating back to the early Islamic period (Figs. 7 & 8, Table 2).

- Historical and archaeological evidence of the study area in the middle Islamic era
Tarrom also reappears in historical texts of the Mongol era due to its strategic location on the route to northern regions, particularly Gilan, and its proximity to key centers like Soltaniyeh (cf. Ibn Khaldun, 1984: vol. 4, 204; Hafez Abro, 2001, vol. 2: 572, 717, 766). The most accurate description of the Tarrom region at this time is provided by Hamdullah Mostofi Qazvini (d. 750 AH), who wrote:
“Tarromain is a warm province to the north of Soltaniyeh, a day’s journey away, and the harvest is very good in its highlands, and most of the fruits of Soltaniyeh come from there. At first, there was a city center called Firuzabad in the land of Lower Tarrom, but now it is completely ruined, and the town of Andar in Tarrom Olya has become the city there... The people of that province are Sunni Shafi’i, and that province has five parts: First, Upper Tarrom (Olya) was a vassal of Qala Taj, it includes about a hundred villages, and Jezla, Shawarzad, Darram, Jiya, Qalat, Zarand, and Shind are among its most important villages... (Mustofi, 1957: 71). Mustofi’s reference to Darram is the oldest reference to this place in historical texts.
At least seven sites in the study area in the villages of Abbar and Darram, including Abbar Cemetery, Torobar, Mine-Bala, Sibison, Dam, Kelavlagh, and Imamzadeh Vazneh-Sar, have had medieval Islamic pottery, especially Seljuk-Ilkhani pottery. These potteries are mostly glazed, sufficiently fired, and have various types of decoration, especially incised patterns, incised patterns under the glaze (Sgraffito), and underglaze painting (Table 3, Figs. 9 & 10).

- Historical and archaeological evidence of the study area in the later Islamic era
Historical records indicate that the Tarrom region remained of interest to Safavid rulers due to its proximity to important Safavid centers like Ardabil and Qazvin. For example, in 911 AH, Shah Ismail spent winter in Tarrom (Badlisi, 1998: Vol. 2, 137), and in 969 AH, Shah Tahmasb went to Tarrom for hunting (Ibid: 217). Pietro Della Valle, who traveled to the Tarrom region via Ardabil in 1619, during the reign of Shah Abbas I, reached Darram village through a narrow and difficult valley (Della Valle, 2005: 331-332). Della Valle’s description contains important information about the geographical features and communication routes of the region during the Safavid period.
From an archaeological point of view, some pottery sherds from the site of Burhan al-Saltaneh date back to the Timurid-Safavid period (Table 4 & Fig. 11). Notably, glazed pottery, including azure-glazed pieces likely from the Seljuk era, and monochromatic pottery with green, blue, and turquoise glaze possibly from the middle or late Islamic period, have been discovered at the study sites.
During the Qajar period, Tarrom continued to serve as a route for royal campaigns and recreational activities, with notable figures like Agha Mohammad Khan, Fath Ali Shah, and Naser al-Din Shah visiting the region (Fasai, 2003: Vol. 1, 645, & 720; Etemad al-Saltanah, 1988: Vol. 3, 1605). During this period, Rawlinson, while traveling to the region, mentioned Abbar and Darram as the two main places in the region of Posht kouh (Rawlinson 1840: 62-63). According to Rawlinson’s description, it is likely that part of the facility known today as Darram Castle is remains of the palace of Abdullah Mirza (d. 1263 AH), the son of Fath Ali Shah who was the ruler of Zanjan during the Qajar period. Based on our survey, Darram Castle is a large site dating back to the pre-Islamic and Islamic period, covering an area of about 20 hectares.
Additionally, based on the architectural style and type of materials, a number of buildings in the study area, including mosques or Imamzadeh, probably belong to the late Islamic period (mostly Qajar), of which we can mention Siahroud Bath, Imamzadeh Ebrahim, Imamzadeh Khatun Khadijeh, Burhan-ol-Saltaneh Mansion, Khasareh Bath, Khasareh Mosque, Molanour, and Imamzadeh Vazneh-Sar.

Conclusion
The analysis of historical texts and archaeological evidence provides valuable information about the settlements in the Tarrom region during the Islamic period, including the size of the settlements and communication routes in this region. Based on the data in Table 5, which was calculated based on our field survey, eight sites (44 percent) are less than one hectare in size. Eight sites are between one and five hectares (44%), and only three sites of Gerdeh Tepe, Tepe Qabristan, and Qala’e Darram are larger than five hectares, all three of which are located along the Qezel Uzan valley, along the main roads of the region. However, compared to the cities of the Islamic era, even these three sites are not considered large settlements. The map in Fig. 12 shows the distribution of Islamic sites in the study area regarding their sizes. Overall, these statistics indicate that most of the settlements in the Islamic period in the study area were, in fact, small, rural settlements, which is in exact accordance with the medieval geographers’ descriptions of the Tarrom as a region with numerous villages but no major city (see: Hamawi 1995: Vol. 2, p. 6; al-Baghdadi, 1412: 249).
It seems that Darram Castle can be considered a central settlement in the Islamic period in the Tarrom region due to its vast size of more than 20 hectares and its special location in the middle of the Qezel Uzan River valley, and the availability of important environmental components such as access to water resources and communication routes. Considering the description of Della Valle and the location of the Islamic sites in the study area, mainly in the Qezel Uzan River valley, it seems that the old roads in the study area were in accordance with the topographic conditions of the region and to a large extent coincided with or were close to the modern road.