Mawlay Hassan bin Mohammed (Arabic: الحسن بن محمد, romanized: al-Ḥasan bin Muḥammad), known as Hassan I (Arabic: الحسن الأول, romanized: al-Ḥasan al-Awwal), born in 1836 in Fes and died on 9 June 1894 in Tadla, was a sultan of Morocco from 12 September 1873 to 7 June 1894, as a ruler of the 'Alawi dynasty.

[18] Of strong Arab culture, he did not know any foreign language,[16] although Mawlay Hassan I was a conservative ruler, he realised the need for modernization and the reform policy of his father.

[16] He strived to maintain the cohesion of his kingdom through political, military, and religious action, in the face of European threats on its periphery, and internal rebellions, He initiated reforms.

He did not hesitate to appoint local qaids like Sheikh Ma al-'Aynayn who gave him the Bay'a, the pledge of allegiance in Islamic Sharia law.

[16][19] Sultan Hassan I managed to maintain the independence of Morocco while neighbouring states fell under European influence, such as Tunis which was conquered by France in 1881 and Egypt which was occupied by Britain in 1882.

The new and reformed 'Askar al-Nizami introduced by sultan Abd al-Rahman in 1845 after the Battle of Isly was expanded by Mawlay Hassan I to the size of 25,000 men and 1,000 artillery.

The sultan also enhanced the Moroccan coastal defences with batteries of large caliber cannon, and in 1888 built an arms factory in Fes known as Dar al-Makina, however production in it was little and costly.

[24] To train the reformed Moroccan army, Mawlay Hassan I sent students to London, but in 1876, the sultan hired Harry MacLean, a British officer based in Gibraltar, who designed a military uniform in Arab-style, and learned to speak excellent Arabic.

[26] The Krupp cannon he gave on this occasion to the qaid of Telouet (member of the now famous Glaoua family) is still on display in the center of Warzazat.

That same year the Touat and the oases which lay along the Oued Saoura were placed under the authority of the son of the Moroccan khalifa who resided in the Tafilalt.

In 1892 and 1893, the Moroccans further solidified their control in the Guir-Zouzfana basin and along the oued Saoura by investing with official authority the qaids from all of the nomadic and sedentary tribes of the region (this included the Doui Menia and Oulad Djerir tribes, the most important nomads of the Guir-Zousfana basin; the oasis of Igli; and the sedentary Beni Goumi people who lived along the banks of the Oued Zouzfana).

From her marriage to the sultan she had:[43] Lalla Oum al-Khair,[45] her last name is not retained, together they had:[45] Lalla Oum Zayda,[47] her last name is not retained, together they had:[47] Sultan Moulay Hassan I is also the father of: Moulay Hassan I had a harem of slave concubines (jawari), however the precise number of his slave concubines is largely unknown, leaving room for speculation.

Since the army was still in enemy territory, his chamberlain and Grand Wazir Ahmad bin Musa kept the death a secret, ordering the ministers to not reveal the news.

[54] Mawlay Hassan was succeeded by his son Abd al-Aziz, thirteen years old at the time, and ruled under the regency of his father's former Grand Wazir, Ahmad bin Musa, until his death from heart failure in 1900.