The Walled Oasis Complex in north-west Arabia

The recent identification of a Walled Oases Complex in north-west Saudi Arabia signals a radical shift in our understanding of the socioeconomic evolution of this vast, largely unexplored region (Charloux et al. Reference Charloux, AlMalki and AlQaeed2021, Reference Charloux2024a). A walled oasis—a term employed in local and distant desert contexts since the early twentieth century at least (e.g. Carruthers Reference Carruthers1922: 408; Jonas Reference Jonas1928)—is defined as an oasis that is surrounded by outer walls (Figure 1). These extensive defensive structures enclosed and protected not only settlements but also water sources, livestock (mainly goats and sheep) and crops (including cereals, fruits and, from the second millennium BC, date palms). Outer walls, serving as a display of power as well as a means of protection, required substantial investments from local populations not only for their initial construction but also for maintenance and modification over time.

Figure 1. 3D reconstruction of the Late Iron Age western enclosure in Dumat al-Jandal walled oasis (© Dumat al-Jandal Archaeological Project; figure by M. Bussy & G. Charloux).

Six walled oases were recently identified within this north-west Arabian complex (Charloux et al. Reference Charloux, AlMalki and AlQaeed2021; considered for the UNESCO World Heritage list https://whc.unesco.org/en/tentativelists/6575/). The walled oases of Tayma and Qurayyah have been known to archaeologists for a long time, four more were identified through satellite images and needed confirmation: Dumat al-Jandal, Hait, Huwayyit and Khaybar.

Over the past three years, researchers have identified potential smaller walled oases (Al-Ayn, Shayb Suways and al-Wadi; Dalton et al. Reference Dalton2021: note 8) and the gradual overlap of funerary avenues by ramparts in the Harrat Khaybar, providing a picture of the evolution of the local protohistoric landscape (Charloux Reference Charloux2024b). In 2024, the walled oasis of Khaybar was also confirmed and dated to approximately 2250−1950 BC (Charloux et al. Reference Charloux2024a).

Analysis of Bing and Google Earth satellite images and field visits to the oases of Al-Ayn and al-Tibq in the Harrat Khaybar (Figures 2 & 3) reveals that their surrounding ramparts (2m thick and around 8 and 2km long, respectively, at their initial construction) have typologically comparable bastions to those of Khaybar, suggesting contemporaneity around 2000 BC. This date is further supported by the recovery of similar burnished ware during surface collection at all three oases. Shayb Suways, whose wall is estimated to have been 8km long, may have also been a walled oasis, although it appears very narrow, while the layout of the walls at al-Wadi does not yet permit the reconstruction of a walled oasis (Figure 4).

Figure 2. The walled oasis of al-Ayn reconstructed on Google Earth (A), and aerial views of the rampart (B) with abutted bastion (C) and inner masonry (D) (figure by G. Charloux).

Figure 3. The walled oasis of al-Tibq reconstructed on Google Earth (A), and aerial views of the rampart (B) with abutted bastion (C) (figure by G. Charloux).

Figure 4. A) Long wall observed in Al-Wadi; B) enclosure wall at Shayb Suways reconstructed on Bing maps; C) walls identified in Al-Wadi on Google Earth (figure by G. Charloux).

In-depth examination of the georeferenced 1964 aerial photographs of the Dumat al-Jandal oasis brings to light a vast network of mudbrick walls approximately 2km long in the eastern part of the oasis, near the sabkha (mudflats), complementing a recent reconstruction (Charloux et al. Reference Charloux, AlMalki and AlQaeed2021) and affirming its identification as a walled oasis (Figure 5).

Figure 5. Map of the walled oasis of Dumat al-Jandal, with a focus on the eastern enclosure seen on 1964 aerial photographs (© Dumat al-Jandal Archaeological Project; figure by G. Charloux).

The walled oases through time and space

Our research provides evidence for the existence of a dense and long-lasting Walled Oasis Complex in north-west Arabia. Although there is only limited documentation and a preliminary chronological framework, this local phenomenon seems to have emerged in the first half of the third millennium BC at Tayma and Qurayyah (Hausleiter Reference Hausleiter, Nehmé and Al-Jallad2018; Lüthgens et al. Reference Lüthgens, Luciani, Prochazka, Firla, Hoelzmann and Abualhassan2023; Figure 6B), possibly inspired by urbanisation concepts in the southern Levant, and spread to the Harrat Khaybar at the end of the third millennium (Khaybar, al-Ayn, al-Tibq and perhaps al-Wadi). The classification of Dadan/al-Ula remains uncertain in the Bronze and Iron Ages, although several thick walls are reported in the wadis and were recently found at Khuraybah (Rohmer pers. comm.). Later, the walled oasis of Dumat al-Jandal attests to the construction of vast fortifications at the end of the first millennium BC, while the phenomenon appears to spread to Thaj in eastern Arabia during the third century BC (Rohmer et al. Reference Rohmer2018).

Figure 6. Preliminary chronology and geographic distribution of the Walled Oasis Complex in north-west Arabia (figure by G. Charloux).

Although the walled-oasis model was occasionally replaced by less static defensive structures in later periods (e.g. Hegra), the enclosure of several sites persisted and the walls continued to function until the twenty-first century (through restoration work) (Figure 6A). Other types of walled oases, of more modest dimensions and conceptualisation, developed later. Medinah, for example, whose early nineteenth-century plan included vast agricultural zones, may be considered a walled oasis (Burckhardt Reference Burckhardt1829: 320 map). Confirmations of enclosed agricultural areas that included the old villages at al-Ula and Anaizah also testify to the continued use of this adapted model in the nineteenth–twentieth centuries (Doughty Reference Doughty1888: 146; al-Huwaytir Reference al-Huwaytir1999; Charbonnier et al. Reference Charbonnier2022).