Except for the opinion of those who began the dating system with Muḥarram of the year following the Hijrah, counting none of the remaining months of that first year—from Rabīʿ al-Awwal to its end. This view was reported by al-Bayhaqī and adopted by Yaʿqūb ibn Sufyān al-Fasawī, who explicitly stated: Badr in the first year, Uḥud in the second, “Badr al-Mawʿid” in Shaʿbān of the third, and the Trench in Shawwāl of the fourth. This, however, conflicts with the opinion of the majority, for it is widely known that the Commander of the Believers ʿUmar ibn al-Khaṭṭāb fixed the start of the calendar at Muḥarram of the year of the Hijrah.

Mālik, on the other hand, held that it should begin with Rabīʿ al-Awwal of the Hijrah year. Thus there are three opinions in all; and Allah knows best.

The correct view is that of the majority: Uḥud occurred in Shawwāl of the third year, and the Trench in Shawwāl of the fifth—Allah knows best.

As for the sound ḥadīth recorded by both Ṣaḥīḥs (1), transmitted through ʿUbaydullāh, from Nāfiʿ, from Ibn ʿUmar, who said:

“I was presented to the Messenger of Allah ﷺ on the day of Uḥud when I was fourteen years old and he did not allow me to fight; I was presented to him on the day of the Trench when I was fifteen and he gave me permission,”

a number of scholars—among them al-Bayhaqī (2)—have reconciled it by stating that he was presented at Uḥud at the very beginning of his fourteenth year and at the Confederates toward the end of his fifteenth (3).

I would add that it is also possible he meant that, when he was presented on the Day of the Confederates, he had already completed fifteen full years—the age at which youths are allowed to fight—so that no additional reckoning is required.

For this reason, when Nāfiʿ conveyed this ḥadīth to ʿUmar ibn ʿAbd al-ʿAzīz, the latter said, “This marks the boundary between minor and adult,” and he circulated it to the provinces. The majority of scholars have relied upon this criterion, and Allah knows best.

Here is the sequence of events as related by Ibn Isḥāq and others:

Ibn Isḥāq (4) said: The expedition of the Trench took place in Shawwāl of the fifth year. Yazīd ibn Rūmān told me, on the authority of ʿUrwah—and others whom I do not suspect—from ʿAbdullāh ibn Kaʿb ibn Mālik, Muḥammad ibn Kaʿb al-Quraẓī, al-Zuhrī, ʿĀṣim ibn ʿUmar ibn Qatādah, ʿAbdullāh ibn Abī Bakr, and other scholars of ours—some of them reporting matters that others did not:

They said: Part of the story of the Trench is that a group of Jews—among them Sallām ibn Abī’l-Ḥuqayq al-Naḍarī, Ḥuyayy ibn Akhṭab al-Naḍarī, Kinānah ibn al-Rabīʿ ibn Abī’l-Ḥuqayq, Hawdhah ibn Qays al-Wāʾilī, and Abū ʿAmmār al-Wāʾilī—together with some men from Banū al-Naḍīr and others from Banū Wāʾil, were the ones who mustered the Confederates against the Messenger of Allah ﷺ.