Thomas Crosses the Empty Quarter

In early 1931, the British diplomat and explorer Bertram Thomas became the first outsider known to have crossed the Rub' al Khali, the "Empty Quarter" of southern Arabia, one of the largest continuous sand deserts on Earth. The date given for this event is 1932, which matches the year Thomas announced his feat to the world and published his account, though the journey itself took place in the winter of 1930-31. His traverse closed one of the last great blanks on the map of the Middle East and made him briefly one of the most celebrated explorers of his age.

The Rub' al Khali covers a vast area of the southern Arabian Peninsula, spanning parts of present-day Saudi Arabia, Oman, Yemen and the United Arab Emirates. Its dunes, some of them towering, and its extreme heat and scarcity of water had long deterred outsiders, while the Bedouin who lived on its fringes knew its wells and grazing grounds well. Thomas had come to the region as a British Army officer and then served as a wazir, or chief adviser, to the Sultan of Muscat and Oman. That post gave him language skills, local contacts and the sultan's goodwill. He was also competing with others, notably the British adventurer St John Philby, who was eager to be the first to make the crossing.

Thomas set out from Salalah on the Omani coast in late 1930 with a party of Bedouin guides and camels, relying on local knowledge and the protection of tribal leaders to move from one water source to the next. He travelled north-west across the sands and eventually reached the Persian Gulf coast near Doha, in what is now Qatar. Along the way he recorded geographical observations, collected measurements and reports of the terrain, and noted the people he met. Some of the desert's wells and the routes between them were mapped for the first time by a European, though they were of course already familiar to the Arabs who used them.

Thomas received honors from the Royal Geographical Society and other bodies, and his book Arabia Felix (1932) became a popular success. Philby completed his own crossing in 1932, taking a different route, and his work added considerably to the knowledge of the desert's interior. Together the two journeys ended an era of Western uncertainty about the geography of southern Arabia.

The legacy of these expeditions is mixed. They advanced scientific understanding and inspired later travel writers such as Wilfred Thesiger, who crossed the Empty Quarter twice in the late 1940s. Yet they also came at the dawn of the oil age, when geographic knowledge of Arabia soon took on commercial and strategic importance. The desert that Thomas crossed would, within a few decades, be explored again by geologists and prospectors.