1
See
 Antiquity
89/ 346, 2015: 885-904 for the published version of this article. Northern outpost of the Caliphate: maintaining military forces in a hostile environment (the Dariali Gorge in the Central Caucasus in Georgia)
 Eberhard W. Sauer
1
, Konstantin Pitskhelauri
2
, Kristen Hopper
3
, Anthi Tiliakou
1
, Catriona Pickard
1
, Dan Lawrence
3
, Annamaria Diana
1
, Elena Kranioti
1
 & Catherine Shupe
1
 
1
School of History, Classics and Archaeology, University of Edinburgh, William Robertson Wing, Old Medical School, Teviot Place, Edinburgh EH8 9AG, UK (Email: eberhard.sauer@ed.ac.uk)
2
 Institute of Archaeology, Ivane Javakhishvili Tbilisi State University, 1 Ilia Chavchavadze  Avenue, Tbilisi 0179, Georgia (Email: kotepi2002@yahoo.com)
3
 
 Department of Archaeology, Durham University, South Road, Durham, County Durham DH1 3LE, UK (Email: k.a.hopper@durham.ac.uk) Keywords:
Georgia, Caucasus, Late Antiquity, early medieval, fortification, isotope analysis, osteoarchaeology
The strategic significance of the Dariali Gorge, the main pass across the central Caucasus and
known as the ‘Caspian’ or ‘Alan Gates’, has long been recognised.
 It features in an arguably wider range of written sources than any other mountain pass in the ancient world and it forms a border today as it has done for much of the past 2000 years. But what strategies were employed to make a hostile crossing of
 Europe’s highest mountain
range as perilous as  possible? And how was an effective military force sustained in an isolated Alpine environment? Excavations, osteoarchaeology and landscape survey during the summer of 2013 (by a team  from Ivane Javakhishvili Tbilisi State University and the Universities of Edinburgh and  Durham) shed fascinating new light on the strategies employed to close this gap in the natural defences. Fieldwork revealed that the Early Middle Ages saw as much investment in controlling this key route as there was in Antiquity.
 
Guarded by the same Muslim-led garrison for at least a quarter of a millennium, its survival in a harsh environment was made possible through military effort and long-distance food supplies.
 
2
Introduction
The territory of modern Georgia has long been on the fault-lines of political influence and expansionist ambitions of major western, eastern and northern powers. Subdivided by mountainous terrain, the west of Georgia was frequently under western influence and the east (Iberia) sometimes under eastern in Antiquity. Yet Iberia was able to reassert a remarkable degree of cultural and political autonomy as its rich economic assets were protected by mountain ranges and it controlled the Dariali Gorge. The interest of neighbouring powers in sealing off the main invasion route across the central Caucasus elevated this remote mountain valley to extraordinary fame across the ancient and medieval world. Pliny the Elder (6.30, 6.40; Brodersen 1996: 30
 – 
31, 36
 – 
37, cf. 175 & 179), Ptolemy (
Geography
5.9.11; Stückelberger & Graßhoff 2006: 534
 – 
35, cf. 536
 – 
37 with no. 164, 850
 – 
51 map 2), Procopius (
Wars
1.10.3
 – 
12; Veh 1970: 64
 – 
67, cf. 465
 – 
66), various sources in Arabic and numerous other texts make reference to it. It also features in inscriptions of the Sasanian King Shapur I (
c
. AD 240
 – 
272) (e.g. Huyse 1999: 22
 – 
23), as well as in the medieval Georgian chronicles (Thomson 1996). The narrow gorge resembled gates and was controlled by gated barriers. It was known as the
Caucasian
,
Sarmatian
 or
Caspian Gates
; the latter name was shared with at least two other mountain passes; additional appellations were the
Gates of Hiberia
 (i.e. Iberia) and the
Gates of the Alans
, an
ethnic group north of the Caucasus. The modern name, ‘Dariali’
, derives from the Persian for
‘Gates of the Alans’.
Persia had temporarily been in control of the Gates in Late Antiquity and the Alans spoke a Persian language, as the Ossetes still do today. The Gates provided one of very few viable traffic routes from the steppes of Eurasia to Transcaucasia and the Near East. Ancient and medieval sources imply that most hostile forces crossing the central and eastern Caucasus did so via the Dariali and Derbent routes, the latter along the coast of the Caspian Sea. Although not impossible to bypass (Braund 2001), other routes involved significantly greater difficulties and risks. It is unsurprising that much effort was invested in controlling movement through the pass, which was first occupied and supposedly fortified by the Iberians (
 Life of Kartli
 28; Thomson 1996: 41; Tacitus,
 
 Annals
6.33; Wuilleumier 1975: 113-14). Later, the famous Gates were the target of a planned military expedition of Nero (Heil 1997: 170
 – 
82, 224
 – 
31, with sources). Some scholars (Gamkrelidze 2012: 91, 97
 – 
98 and Zerbini 2013: 36
 – 
37, 39) argue that Roman troops were stationed in the strategic mountain pass in the later first and second centuries AD; whether correct or not, the Gates appear to have remained part of Iberia. From the third to the seventh centuries the Gates were repeatedly under the direct or indirect control of the Sasanian Empire. The Iberians, then more often in the Persian than Roman sphere of control, still appear to have played a prominent
 
3
role in the defence of the Gates, and in the late fifth and/or early sixth century
a ‘Hun’ named
Ambazoukes was in charge before they were reconquered by the Persians (Procopius,
Wars
 1.10.9
 – 
12). The Persian defences in the Caucasus, and demands for major Roman contributions, feature prominently in negotiations with the Eastern Roman Empire in Late Antiquity (Blockley 1985, with sources)
. Effective control of the Gates kept both Persia’s and Rome’
s Near Eastern possessions secure from the northern threat. The natural mountain barrier of the Caucasus retained its strategic significance throughout the Middle Ages and beyond. In the eighth century, the mountain chain became the boundary between the Caliphate (the largest empire the Mediterranean and Near Eastern worlds had ever seen, stretching from the Atlantic Ocean to the edge of the Indian Subcontinent) and the Khazar Khaganate, a powerful political entity in the steppes. As the Caliphate fractured, the Dariali Gorge became the northern boundary first of the Emirate of Tbilisi and in
 c
. AD 1118 of the Kingdom of Georgia. In the Mongol era it separated the zones of influence of the Ilkhanid Empire and the Golden Horde. As recently as 1942 the strategic significance of the gorge became apparent when German troops, headed for the same route that so many invaders from the north had chosen before them to cross the Caucasus, suffered defeat just 20 miles north of the gorge. Today, a narrow section of the Dariali Gorge, having been borderland for most of the past two millennia, again forms the border of Georgia (Figure 1).
 
4
Figure 1. Geographically determined continuity: the sword-bearer in Grave G9 inspected by a member of the Georgian border police: two frontier guards a millennium apart?
 
5
The archaeology of the
Alan Gates
 
Despite its strategic significance, as reflected by prominent coverage in ancient and medieval sources, the gorge has received little archaeological attention. Pioneering work has been carried out by Georgian archaeologists, most notably by Dr Davit Mindorashvili (2005) who excavated a sondage at Dariali Fort from 1988
 – 
1991, as well as parts of an associated medieval cemetery and a second, early medieval cemetery 2.5km farther south. Dariali Fort is a multi-period stronghold dominating the gorge,
c
. 1km south of a wall on a precipitous ridge (Figure 2). It is widely agreed (e.g. Reineggs 1796: 225
 – 
26; Klaproth 1812: 671
 – 
75; Marquart 1903: 166; Braund 2000 & 2001: 40
 – 
41; Gagoshidze 2008: 19) that this is the key fortification, named
Cumania
 by Pliny (6.30) in the first century and the
‘Alans’ Castle’ by Mas’udi
(17;
 
Barbier de Meynard & Pavet de Courteille 1863: 43
 – 
45) in the tenth century. Both authors offer topographical descriptions that are perfectly compatible with Dariali Fort (Figure 3), with
Mas’udi referring to an impregnable fort on
a massive rock that towers over a substantial river and a bridge, and was capable of blocking all traffic.
Figure 2.
 
 Part of the ‘Alan Gates’: a wall on a precipitous ridge, with Dariali Fort in the
background.
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