Al-Fadl IV, Sultan of Yemen, reigned from 1863 to 1874. During his reign, the Lahej Sultanate was part of the British Aden Protectorate. Al-Fadl IV's reign was a significant one, coinciding with the beginning of British influence in the Aden Protectorate. During his time, the independence of the sultanate decreased due to the increase of British influence. Al-Fadl IV died in 1874, after which al-Fadl III took over the power in the sultanate. The Sultanate of Lahej went through several changes throughout its history, including becoming part of a British protectorate and later the Federation of South Arabia, finally ending in 1967 when South Yemen was proclaimed.

Al-Fadl IV. Sultan of Yemen ruled from 1863 to 1874. During this period, Yemeni coinage underwent significant changes. The sultan introduced modern machines instead of the previous, traditional minting techniques and started minting new types of coins. Al-Fadl IV. its coins include gold coins: 1, 2, 5, 10, 20 and 50 riyals, silver coins: 1, 2, 5, 10, 20 and 50 dirhams, magenta coins: 1, 2, 5, 10 and 20 dirhams. the portrait of the sultan, and the name of the caliph and the title of the sultan on the back. The silver and purple coins had the sultan's title on the obverse, and the sultan's title and mintage year on the reverse. Al-Fadl IV. its coins contributed significantly to the modernization of the Yemeni financial system. During the sultan's reign, the quality and purity of Yemeni coins improved significantly, and the Yemeni monetary system became more transparent and reliable. He introduced modern machines instead of the previous, traditional minting techniques. This made it possible to mint a larger quantity of higher quality coins. Al-Fadl IV. began minting new types of coins, which included gold, silver, and purple coins. This variety contributed to the diversification of the Yemeni monetary system. Al-Fadl IV. the sultan's title was also included on his coins. This served to increase the power and authority of the Yemeni sultans.