Al-Hassan Hamid al-Din ibn Yahya (13 June 1908 – 13 June 2003) was a Yemeni royal and statesman who served as the Prime Minister of the Mutawakkilite Kingdom of Yemen, once from April 1948 to August 1955, a second time from 1962 to 1967, and a third time from 1969 to 1970.

His title was Saif Al-Islam.

Biography He was born at Al-Qaflah, Hashid. Hassan ibn Yahya was the third eldest of the fourteen sons of King Yahya Muhammad Hamid ed-Din.

Before the assassination of his father in February 1948, he served as governor of the provinces of Ibb, Sana'a and Hodeida from 1938 to 1948.

During the 1948 coup attempt, he played a key role in rallying forces loyal to the dynasty in support of his brother Ahmad.

From April 1948 to June 1955, he held the positions of Viceroy and Prime Minister of the Kingdom of Yemen. After the coup attempt by his younger brother Abdullah, he was dismissed from his posts due to suspicions of supporting the coup.

From 1955 to 1962, Prince Hassan served as the Permanent Representative of the Kingdom of Yemen to the United Nations.

In this position, Prince Hassan vigorously defended his country's interests from the UN rostrum. On 23 January 1958, for instance, Prince Hassan stated that on 30 December British troops had carried out a new attack on Yemeni territory north of Aden. Protesting against British actions, Prince Hassan sent a memorandum to Secretary-General Dag Hammarskjöld.

Western perceptions (1958–1962) Western observers viewed Prince Hassan as less militantly anti-Western than his nephew al-Badr. A 1958 CIA intelligence assessment noted that in a succession crisis, al-Badr would likely receive military support from Egypt and possibly Soviet intervention.

British and American officials discussed plans for a coup to replace Imam Ahmad with his brother Hassan, aiming to prevent al-Badr from coming to power. London viewed Imam Ahmad's friendship agreement with Moscow, his embrace of Arab nationalism and his son's pro-Soviet tilt as serious threats.

In February 1958, a British senior officer declared that "the ousting of the present regime must be carried out by local Yemenis, although it is clear that Hassan and his supporters enjoy substantial support from the Americans, alongside our support [the British], the Italians and King Saud"."Note by Kemp". Kew, London: The National Archives. February 1958. CO 1015/1266.

In July 1958, William Luce, the governor of Aden, submitted a proposal to distribute 25,000 shotguns to tribes that supported Hassan. The British thus carried out interventionism in south-west Arabia to a greater degree than ever before.

According to Hatem al-Khalidi, the United States attempted to befriend Prince Hassan and orchestrate the assassination of Imam Ahmad and al-Badr. After Ahmad's death, however, the US State Department refused to intervene in support of Prince Hassan unless Yemen moved too far toward the Soviet Union.

Succession struggle Imam Ahmad demanded that his brother Prince Hassan swear allegiance to al-Badr as his successor. Al-Badr lacked the support of most tribes; they preferred Hassan. During his governorship of the northern districts in the early 1950s, Hassan built a strong network of loyalties among the tribes. He used this network in his struggle with the imam. Ahmad tried to sideline Hassan by appointing him ambassador to the United Nations. The alliance between the Imamate and the Zaydi tribes crumbled, helping to bring about the revolution of 26 September 1962.

Overthrow of the monarchy and Civil War On 27 September 1962, military units led by Colonel Abdullah al-Sallal carried out a coup d'état and overthrew the traditional imamate, which had existed in the region for more than 1,000 years, either as an independent political entity or under formal Ottoman sovereignty.

After the overthrow of the monarchy in September 1962, on 28 September Prince Hassan went to the mountains in the north of the country. On 29 September, he declared his intention to return home and claim the 1,000-year-old family throne. On 30 September he moved to Saudi Arabia and felt confident enough to claim the imamate for himself. From there he called for an uprising against the republican authorities and the "Egyptian invaders".The New York Times (December 8, 1962): "YEMEN RECOVERY VOWED BY PRINCE; Hassan Calls Revolt Work of 'Egyptian Invaders'". Prince Hassan stated that the uprising had been organized by a small group of officers without popular support and promised to suppress it.Al-Hayat (September 29, 1962).

In London, prince Hassan said he had no official information that his nephew al-Badr was dead as the rebels claimed. The Yemeni legation in London declared that Hassan was now the legal imam and king. In Frankfurt, the Yemeni envoy said he had received word through diplomatic channels that Hassan had been proclaimed the new king. The same envoy asserted that the rebellion had been provoked from the outside by a foreign power, which he did not name. A member of the Free Yemeni Movement in Cairo warned that if Hassan set foot on Yemeni soil, he would be killed. Middle Eastern broadcasts reported that Saif Al Islam Ismail, al-Badr's uncle, and Saif Al-Islam Mohammed Amin Ahmed, al-Badr's brother, were leading tribes against the rebels in Sana'a. Other reports said that Yemeni royal princes had sent their families to Saudi Arabia for shelter.

The Hamidaddin family sought to restore the monarchy in Yemen, but it is widely recognized that without Saudi support the Yemeni royalists would never have been able to offer significant resistance to the republican government, let alone sustain it for more than seven years.U.S. News & World Report (December 31, 1962). The same can be said about the republican government, which enjoyed massive military and political support from Egypt.

However, before Prince Hassan left New York,World Student News, Volumes 16–17 (1963), p. 11. Jordan instructed its representative at the United Nations to convey its recognition of al-Hassan. During a stop in London, Prince Hassan declared: "I will restore order in Yemen. The people will rise up against the revolutionaries". The northern Yemeni tribes that supported al-Hassan sought to restore the imamate and the Hamidaddin monarchy.

On 28 September, by decision of the new authorities, 10 former government officials were executed, including former Foreign Minister Hassan bin Ibrahim. Abdullah al-Sallal ordered the execution of princes of the deposed dynasty, but failed to capture Prince al-Hassan, one of the most dangerous enemies of the new republican regime.

On 30 September al-Hassan arrived in Saudi Arabia, and on 5 October, having secured the support of King Saud bin Abdulaziz Al Saud, he announced the formation of a royalist government in exile. As head of the royalist government-in-exile, Prince Hassan became one of the principal political figures through whom the Yemeni royalist movement interacted with regional and international actors. The conflict rapidly evolved beyond a purely domestic struggle, drawing in Saudi Arabia as the chief supporter of the royalists and Egypt as the principal backer of the republican regime. The resulting confrontation transformed the Yemeni Civil War into a major arena of inter-Arab rivalry and attracted the attention of both the United Nations and the United States, which sought to prevent a wider regional escalation.

He immediately began sending princes of the royal family to the northern Yemeni tribes, offering them gold and weapons in exchange for loyalty. In early October, Jordan sent a mission to Jeddah to provide military support to the Yemeni royalists. Jordan also organized arms supplies for the Yemeni royalists.

On 4 October 1962, the Yemeni legation in Amman announced that the eastern and northern tribes had joined Prince Hassan and claimed that Sana'a would soon be encircled.

Immediately after the coup, Prince Hassan ibn Yahya was proclaimed the new King of Yemen. However, once it became known that the deposed King Muhammad al-Badr had survived the coup, on 16 October Prince Hassan renounced his claims to the throne and recognized al-Badr as the legitimate monarch of the country.

Mecca radio reported that al-Badr had set up headquarters near Hajja, about 70 miles northeast of Sana'a, and was massing forces to overthrow the rebel regime. Hassan relinquished his claims to the throne after being named royal premier.

Notably, before the fate of the deposed Imam al-Badr was clarified, Saudi Radio Mecca reported: "100,000 Yemeni warriors are ready to support King Hassan". In response, Abdullah al-Sallal declared: "We are ready for war. If necessary, we will transfer the war to Saudi Arabia as well".

On 8 October 1962, the Yemeni legation in Washington reported that it had received a message from Prince Hassan that his troops would soon surround Sana'a, while royalist sources in Amman claimed that Wadi Ahmed al-Siagi had entered North Yemen to join Hassan. The reports further stated that al-Siagi would head the royalist government as premier, while Hassan concentrated on securing tribal backing and organizing a military campaign against the republican regime.The New York Times (Oct. 9, 1962): "Royalists Claim Gains".

On 12 October, the Foreign Minister of the "old regime" stated that royalist forces had captured three Soviet officers who, according to him, had helped the rebels seize power on 27 September.The New York Times (Oct. 14, 1962): "YEMENI REPORTS 3 RUSSIANS SEIZED; Aide of 'Old Regime' Says Officers Were Taken Says Troops Advance Cairo Sends High Aides Government's Needs Stressed Republicans Claim a Victory".

In mid-October 1962, according to the Egyptian Middle East News Agency, Imam al-Badr, who had suffered a serious leg injury during the coup, was in an American hospital in Dhahran. According to Radio Amman, Imam al-Badr sent a message to jordanian king Hussein I condemning Nasser's interference in Yemen's internal affairs. On the other hand, the Egyptian newspaper Al-Ahram reported that al-Badr had stated he was abandoning all political activity. At the same time, Egypt spread information that Prince Hassan himself had been killed at the front in Marib and buried in the Protectorate of Lahij.

On 19 October 1962, Sana'a radio announced the death of Crown Prince Hassan. The Yemen Arab Republic government ordered his property and that of fifteen other members of the royal family confiscated, an approximate total of 40,000 acres. On the same day, Sana'a radio also reported that a revolutionary high court had sentenced Prince Hassan and thirteen other members of the royal family to death in absentia. The sentences were confirmed by President Abdullah al-Sallal. The court also declared their passports invalid. Radio Mecca reported that Hassan and the other royal family members were outside Yemen.

During the North Yemen Civil War, many members of the royal family took an active part in the fight against the republican government. Prince Hassan served as Prime Minister of the government in exile (1962–1967 and 1969–1970). Prince Abdul Rahman bin Yahya was Deputy Prime Minister and one of the commanders of the royalist forces.

The royalists used a strategy of wearing down the enemy. As Prince Hassan stated: "...our current tactic is to surround the cities without entering them. This saves the civilian population from heavy losses. This prolongs the war, but will not prevent us from achieving our ultimate goal..."Le Monde (08 août 1963): "III. - " Le socialisme ? Quel vilain mot !... "".