Muḥammad, the son of Ḥasan 'alá dhikrihi's-salám, died on September 1, A.D. 1210, and was succeeded by his son, Jalálu'd-Dín, who utterly reversed the policy of his father and grandfather, abolished all antinomianism, and declared himself an orthodox Muslim, whence he was known as Naw-Musul-mán , “the New Musulmán,” or “Convert to Islám.” He made formal profession of his fealty to the 'Abbásid Caliph an-Náṣir li-díni'lláh, entered into friendly relations with the surrounding Muslim princes, sent his mother (in A.D. 1210) to Mecca to perform the Pilgrimage, and, in order to con­vince the doctors of Qazwín (who, as near neighbours of Alamút, were least inclined to believe in the bonâ fide character of his conversion) of his sincerity, invited them to send a deputation to inspect his libraries and destroy all such books as, in their opinion, savoured of heresy. All were at last convinced of the genuineness of his professions, and the Caliph showed him honours so marked as to arouse the jealousy of Khwárazmsháh, and cause the beginning of that estrangement between Khwárazm and Baghdád which had such fatal results. * He also allied himself with the Atábek Mudhaffaru'd-Dín Uzbek (A.D. 1213-15) against Náṣiru'd-Dín Manglí, and—alone of the Grand Masters of Alamút— resided for a year and a half beyond the shadow of his fast­nesses in 'Iráq, Arrán, and Ádharbayján. Later he allied himself with Jalálu'd-Dín Khwárazmsháh, but, on the appearance of Chingíz Khán on the scene, he deemed it prudent to tender his allegiance to him, his ambassadors being the first to do homage to the heathen conqueror when he crossed the Oxus. This act probably put the final touch to the disgust which his actions had inspired in the sect of which he was the supreme pontiff, and very shortly afterwards, on November 2 or 3, A.D. 1220, he died suddenly, poisoned, as it was supposed, by some of his women. He was succeeded by his only son, 'Alá'u'd-Dín, then only nine years of age, whose wazír acted at first as his regent, and inaugurated his reign by putting to death, even by burning, a number of the late Grand Master's female relatives whom he suspected, or pretended to suspect, of complicity in the death of Jalálu'd-Dín Naw-Musulmán .

According to Rashídu'd-Dín, 'Alá'u'd-Dín, when about fifteen years old, developed a moody melancholia which made it dangerous to approach him with any unwelcome news, or to inform him of any circumstance likely to displease him. During his reign the great astronomer Naṣíru'd-Dín Ṭúsí, author of the well-known treatise on Ethics known as the Akhláq-i-Náṣirí, was kidnapped by Náṣiru'd-Dín, the Isma'ílí Governor of Quhistán, * and sent to Alamút, where he remained as an honoured, if unwilling, guest until it was captured by the Mongols. This fact has a double im­portance, literary and historical: literary, because, as already remarked (p. 220 supra), it is probable that, by confusion of names, a garbled version of it was incorporated in the pseudo-autobiography of Náṣir-i-Khusraw, who lived more than a century and a half earlier; historical, because it was Naṣíru'd-Dín Ṭúsí who first induced the unfortunate Ruknu'd-Dín Khursháh, of whom we shall speak directly, to surrender himself into the hands of the perfidious Mongols, * and after­wards persuaded Hulágú, when he was deliberating on the fate of al-Musta'ṣim bi'lláh, the last 'Abbásid Caliph, that no heavenly vengeance was likely to follow his execution. * What irony that this double-dyed traitor should be the author of one of the best-known works on Ethics written in Persian!

'Alá'u'd-Dín married very young, and his eldest son Ruknu'd-Dín Khúrsháh was born when he was only eighteen years of age. Between him and this son, whom he originally nominated as his successor, so great a jealousy gradually grew up that he desired to revoke this nomination; but the Isma'ílís, acting on their old principle, that an explicit nomination to the Imámate by an Imám was irrevocable, refused to allow it, and on the last day of Shawwál, A.H. 653 (= December 1, A.D. 1255), 'Alá'u'd-Dín was found murdered at Shír-kúh. The actual murderer, Ḥasan of Mázandarán, was killed by order of Ruknu'd-Dín, and his body was afterwards burned; but it was believed that Ruknu'd-Dín himself incited Ḥasan to do this deed, in proof of which Rashídu'd-Dín adduces the fact that he caused Ḥasan to be assassinated instead of dealing with him by more regular and legal methods, for fear of the disclosures which he might make under examination. This historian, after remarking that no parricide escapes the swift and condign vengeance of Heaven (in proof of which he cites the cases of Shírúyè the Sásánian and al-Muntaṣir, the 'Abbásid Caliph, both of whom murdered their fathers and lived but a short while to enjoy the fruits of their crime), points to the curious coincidence that Ruknu'd-Dín finally surrendered himself into the hands of his destroyers on the last day of Shawwál, A.H. 654 (= Sunday, November 19, A.D. 1256), exactly a year, according to the lunar reckoning of the Muḥammadans, after his father was found murdered.

We must now return to Hulágú's expedition, which we left at Kesh in January, 1256. Tún and Khwáf, two of the strongholds of the Assassins in Quhistán, were the first places to bear the brunt of his attack. Both were taken about the end of March, 1256, and all the inhabitants of the latter over ten years of age were put to death, save a few girls of exceptional beauty, who were reserved for a worse fate. Then began the usual tactics of the Mongols, who, as already said, were wont to gain all they could by lying promises ere they unsheathed the sword which no oath could blunt and no blood satiate. Ruknu'd-Dín, torn by conflicting fears, had neither the courage to resist to the bitter end nor the prudence to seek by a full and instant submission the faint chance of a prolonged though ignominious life. He tried to bargain, but always it was he who gave while the Mongols merely promised, ever tightening their nets upon him. He surrendered some of his strongholds on the understanding that the garrisons and inhabitants should be spared, and sent his brother, Sháhinsháh, with 300 other hostages, to Hulágú; but soon, on some pretext, Sháhinsháh was put to death at Jamál-ábád, near Qazwín (whence, says Juwayní, the Qazwínís were after­wards wont to use the expression “sent to Jamál-ábád” as a euphemism for “executed”), and at a later date all the Isma'ílís who had surrendered, even to the babes in their cradles, were ruthlessly slaughtered. Some of the stalwarts were for a desperate resistance, and, even after Ruknu'd-Dín Khúrsháh had sought and obtained from Hulágú Khán a yerlígh, or written guarantee of safety, they repulsed a Mongol attack with great slaughter. But, as already said, the end came on November 19, when Ruknu'd-Dín gave himself up to the Mongols, and Alamút and Maymún-Dizh were pillaged and burned. 'Aṭá Malik-i-Juwayní obtained permission from his master, Hulágú, to select from the world-renowned library of Alamút such books as he deemed most valuable and free from all taint of heresy, as well as some astronomical instru­ments which he coveted, and he has also left us a pretty circumstantial account of the strong and cunning workman­ship which made the Castle of Alamút so long impregnable. According to a historical work by Fakhru'd-Dawla the Buwayhid which he found in the library, it was originally constructed by one of the princes of Daylam in A.H. 246 (= A.D. 860-61). Of the remaining strongholds of the Assassins in Persia (for the Syrian branch was never extirpated in such fashion, and their remnants still exist in that country), Lamsar was taken on January 4, A.D. 1257, while Gird-i-Kúh was still unsubdued in A.H. 658 (= A.D. 1260), when Minháj-i-Siráj was writing his Ṭabaqát-i-Náṣirí (ed. Nassau Lees, p. 418).

As for the unfortunate Ruknu'd-Dín, he was taken to Hama-dán, and was at first well treated by his captors. A Mongol girl for whom he had conceived a passion was given him to wife, and he was presented with a hundred dromedary stallions, whom it pleased him to see fight with one another—a taste more degraded, if not less appropriate to his condition and pretensions, than his father's eccentric fancy for pasturing sheep. But on March 19, A.D. 1257 (at his own request, according to Juwayní and Rashídu'd-Dín, though this we may be permitted to doubt), he was sent off under escort to Qaráqorum to appear before Mangú Khán, the Mongol Emperor. On the way thither he was compelled to summon his officers in Quhistán to surrender their castles, of which the inhabitants, in spite of promises of safety, were of course massacred by the Mongols as soon as they had left the shelter of their walls, 12,000 of them being put to death in Quhistán alone. At Bukhárá Ruknu'd-Dín was roughly handled by his warders, and, on his arrival at Qaráqorum, Mangú Khán ordered him to be put to death, observing that it was a pity that the post-horses had been uselessly fatigued by bringing him so far, and issuing instructions that all of his surviving followers were to be ruthlessly destroyed. Vast multitudes must have perished, without doubt, but not all, for remnants of the sect, as I was informed by a very intelligent and observant Bábí dervish of Kirmán, of whom I saw a great deal when I was in Cairo in the early part of the year 1903, still exist in Persia, while in India (under the name of “Khojas” or “Khwájas”) and Chitrál (under the name of “Mullás”), as well as in Zanzibar, Syria, and elsewhere, they still enjoy a certain influence and importance, though it requires a great effort of imagination to associate their present pontiff, the genial and polished Ághá Khán, with the once redoubtable Grand Masters of Alamút and the “Old Man of the Mountain”—“Le Vieux” of Marco Polo's quaint narrative.