A battle took place during the era of Hazrat Umar (ra), which is known as the Battle of Rayy. Rayy is a very well-known mountainous area. It is located at a distance of 480 miles from Nishapur and 51 miles from Qazvin. The inhabitants of Rayy are called by the name “Razi”.
The well-known commentator of the Holy Quran, Hazrat Imam Fakhr-ud-Din Razi was from Rayy.
Sia Baksh bin Mahran bin Bahram Shubin was the ruler of Rayy. He called [the people of] Dunbawand, Tabaristan, Qumis and Jurjan for help and told them that the Muslims have attacked Rayy. He ordered them to gather in order to confront them, otherwise they would not be able to fend them off individually. Subsequently, the supporting armies from these areas gathered in Rayy as well. The Muslims were still on route to Rayy, when a Persian chief, Abul-Farkhan Zainabi, approached the Muslims in order to make peace. The reason for this was most probably that he had fallen out with the ruler of Rayy.
When the army reached the city, there was a significant disparity between the size of the Muslim army and that of the opposing army. Having observed this, Zainabi said to Nu‘aim, “Send some of your cavalries with me. I will enter the city through a secret passage. You should then launch an attack from outside and the city will be conquered.”
Hence, during the night, Nu‘aim bin Muqarrin sent some of his cavalry along with Zainabi, under the command of his nephew, Munzir bin Amr. He himself took his army and launched an attack on the city. The battle commenced and the enemy firmly stood its ground and fended off the attack. However, when they heard the slogans of the Muslims, who had set off with Zainabi, from behind them, they lost all hope and the Muslims conquered the city. The inhabitants of the city were given a written oath of protection and the words of this agreement were as follows:
“In the name of Allah, the Gracious, the Merciful. This is the settlement, which Nu‘aim bin Muqarrin gives to Zainabi. He will protect the inhabitants of Rayy and the people in its surroundings on the condition that every adult pays the jizya [tax] according to their capacity and acts in goodness. They should show them the way [for their onward journey] and not be dishonest and deceitful. They should extend their hospitality to the Muslims for the duration of one day and they should honour them. Whoever abuses a Muslim verbally will be punished and whoever attacks a Muslim will be punished by death.” In any case, this was the settlement and was attested.
(Mir Mahmud Ahmad Nasir, Muqala Tarikh-e-Islam bi-Ehd-e-Hazrat Umar (ra), pp. 170-172) (Muhammad Ibn Jarir al-Tabari, Tarikh al-Tabari, Vol. 2 [Beirut, Lebanon: Dar al-Kutub al-Ilmiyyah, 2012], p. 537) (Yaqut Ibn Abd Allah al-Hamawi, Mu‘jam al-Buldan, Vol. 1 [Beirut, Lebanon: Dar Ihya al-Turath al-’Arabi], p. 511) (Ibid., Vol. 3, p. 132)