The Expedition of Tabuk, also known as the Campaign of Hardship, was a military campaign that was initiated by the Islamic prophet Muhammad in October 630 CE, in response to reports of a potential Byzantine invasion of northern Arabia. He led a force of as many as 30,000 north to Tabuk, near the Gulf of Aqaba, in present-day northwestern Saudi Arabia. Although no direct battle occurred, the campaign was significant for asserting Muslim presence in the region and securing strategic alliances.