Yemeni-Omani War

Following a secretive deal between Jabal Shammar & the (out of power) Imam of Oman, both Jabal Shammar & the Sultanate of Yemen would conduct an invasion into the territory; Yemen, with the hopes of annexing Dhofar & Wusta, the regions of Oman closest to they, and Jabal Shammar, with the hopes of further unifying the Arabian peninsula by deposing the Sultan and setting up an Imamate in the country, who would act as their puppet. Later in the war, the Kingdom of Portugal joined on the side of Yemen and Shammar, capturing the island of off the coast of Oman.