Abstract
Aligudarz County is one of the cold regions of Lorestan province, which is located in the east of the Lorestan province. Green pastures, high altitude, abundant water resources and the proximity of this region to the Khuzestan plain have provided a suitable conditions for the formation of nomadic life in this region. From prehistoric times, this region is connected to the lowland areas of northern Khuzestan by many nomadic roads. One of this nomadic roads is Khalilābad/Nomkul which passes through a difficult path along the roaring rivers “Bakhtiari” and “Sarkhao”. During the late Islamic century this road have been used by tribes of Bakhtiari Tribe Federation which they spent the summer in the northeastern part of Lorestan, ie in Aligudarz and Azna, and on the slopes of Oshtrankooh, Qalikuh and winter in Lali and around Dezful. Due to the fact that this road have not been studied so far and have not been well introduced, Independent research was necessary to identify and introduce them. The purpose of this study is to introduce this road and evaluate and analyze the history of the formation of related facilities based on archaeological evidence. The main question of the research is what archeological evidence remains from this road and what period do these works belong to? Research findings are provided through field works. As a result of this study, four bridges, a large part of the cobblestone road, a cemetery and an inscription were identified. The study of these works shows that this road and the collection of works of its route was built in the Safavid period.
Keywords: Lorestan, Aligudarz, Nomkol, Nomadic Road, Safavid Era.

Introduction
Nomadism has a long history in Zagros and Lorestan, this way of life in central Zagros in general and in Lorestan in particular started from the Neolithic period and was completely prevalent in the chalcolithic age. And after that, it has been prevalent in this region in almost all periods. Today, it still exists in many parts of the region. The path of the nomads is called Eil-Rah or Koch-Rah. In most cases, this roads are the most convenient and closest way to travel from Sardsir to Garmsir and vice versa, which are formed according to geographical and biological features. One of the main roads of immigration of Bakhtiari tribes is the so-called Khalilabad-Pole Koll road. This connects the mountainous and cold region of eastern Lorestan to the tropical region of the northern part of Khuzestan. Today, this road is used by tribes from the Chaharlang branch of the Bakhtiari tribe, who spent their summer in the northeastern part of Lorestan, namely in Aliguderz and Azna, and on the slopes of Ashtrankoh, Qalikoh and winter in Sardasht, Lali and around Dezful. This road passes through a very difficult mountain path, along which raging rivers such as Bakhtiari and Sarkhav rivers flow. The efforts of nomadic communities to overcome these natural obstacles have led to the creation of structures and facilities whose examples have been identified in few regions of Iran. This article examines and introduces a part of this road and its facilities in Nomkol region, 22 km southeast of Mergsar village, Mahro district, Aligudarz city, and between Lorestan and Khuzestan provinces.

Research Objectives and Approach
The purpose of this research is to introduce and identify the Khalilabad-Polkol road and the traces of its route and then evaluate the available evidence for dating them. The present research is part of basic research and its approach is based on historical approach. The data have been collected in the usual way of archaeological studies by field visit method. In this method, by visiting the route, its archaeological evidence was identified and documented, and then analyzed using a historical approach.

Introducing the Archaeological Evidence of the Route and the Works Identified Along its Route
The archeological works of this road in the Nomkol area include 3 bridges, a large part of the cobblestone road, a wall in the precipice, a number of cemeteries, temporary settlements and an inscription.
Bridges: The materials used for the construction of bridges are stone and brick (in limited quantity) and its mortar is plaster and mortar. Rubble and plaster mortar were used to build foundations, and bricks were used to build arches, of which little evidence remains today. The foundations of some bridges are rectangular and have triangular breakwater (Gachpezan Bridge No. 1) and one of the bridges has circular foundations. The remarkable thing about the architectural structure of one of the bridges (Bridge No. 1) is that the bridge’s pillar are not in the same direction. Half of the pillars (4 of them) are located on the north bank to the center of the river in one stretch and the other half in one stretch. Concecontlly the bridge has taken the shape of a broken half cross and is fundamentally different from the well-known structure and pattern of bridges that basically form them directly. The structural features of this bridge have not been seen in any of the known bridges in Lorestan and the western region of the country.
Cemetery: There is a cemetery 400 meters west of the Kol bridge and at the confluence of two rivers, Sarkhav and Bakhtiari, where tombstones with designs and inscriptions from the late Islamic era can be seen on some of its graves. This evidence shows that this place was probably one of the resting places along the path of this road.

Cobblestone 
The distance of 12 kilometers from bridge number 1 to the abandoned village at the beginning of Nomkol Valley passes along the edge of Sarkhav River and inside a very narrow valley. In different parts of this road, they have cut rock, created cobblestone and paved road (in dry form or using mortar) and built a wall. In the steep parts of the route, they have created a wall, the height of some parts of which reaches 10 meters. In some parts, by cutting the rock, they have created a narrow way to pass. At the beginning of the route and in the place known as “Tagh Jangi”, they skillfully created a wall 10 meters high and 15 meters long on the body of the rock and created a passageway 150 cm wide. This wall is 20 meters high from the bottom of the valley where the Sarkhav River flows. According to the difference in the arrangement of the stones in the body of the wall, which can be seen on its exterior, two stages of construction can be distinguished in it. Probably, after the initial construction, the wall collapsed in later times and it was restored and rebuilt again. At the end of the path that crosses the west bank of Sarkhav River, a one-kilometer-long cobblestone road has been created using crushed stone and plaster mortar, the minimum width of which is 60 cm, and the maximum is 2 meters. In some parts of this road, small valves have been installed to direct surface water, which pass the water under the road. By passing under the road, these valves direct the water that comes to the surface of the road from the rock west of the road to the riverbed. This road rests on the rock on one side and leads to the river on the other side.

Inscription
On the west bank of Sarkhav River, there is an inscription in Nastaliq script on a rock at the end of the road. The inscription consists of four short lines. The text of the inscription is as follows: “It was finished in the year 1091 by Yusuf Khan, the master of Isfahani”. The content of the inscription refers to the completion of a project in 1091 AH. The intended plan refers to the same paved road and the facilities along its path. This inscription clearly indicates the date of construction of the road in 1091 AH during the Safavid period.

Conclusion
In the current research, one of the nomadic roads in the east of Lorestan province was introduced by relying on archaeological evidence; this road has connected the east of Lorestan province to the northeast of Khuzestan province. In the very difficult parts of this road, which is called Nomkol by the people of the region due to its passage deep in the valleys of the Kul Mountain, they have started to pave the path, build several bridges, create arches and build walls in the precipice points leading to the river. The bridges built along this road, in addition to having some features in common with other bridges in Iran, also have other features that have not been identified in any region of Iran so far. The characteristics of the bridges and the presence of inscriptions on the side of the cobbled road clearly show the construction date of this road and the structures along its path in the Safavid period. This inscription shows that this route was used at least from the Safavid period onwards. Conducting an archeological survey in this area and along the route of this road from Dezful to Aliguderz will reveal more archaeological evidence of this road and other roads in the region.