Then Uparisyena now turned Hindu Kush(Kafiristhan) ? How and History Behind

The earliest known usage of the name the Hindu Kush occurs on a map published about 1000 AD. The Hindu Kush was known in Vedic Sanskrit as upariśyena, and in Avestan as upāirisaēna (from Proto-Iranian *upārisaina- 'covered with juniper').

The mountains remained a stronghold of polytheistic faiths until the 19th century. Pre-Islamic populations of the Hindu Kush included Shins, Yeshkuns, Chiliss, Neemchas Koli, Palus, Gaware, and Krammins.

In the time of Alexander the Great, the mountain range was referred to as the Caucasus Indicus (as opposed to the Greater Caucasus range between the Caspian and Black Seas), and as Paropamisadae by Hellenic Greeks in the late first millennium BC.

In Persian, it is known as the Hindu Kush. Some 19th-century encyclopaedias and gazetteers state that the term the Hindu Kush originally applied only to the peak in the area of the Kushan Pass, which had become a centre of the Kushan Empire by the first century. Some modern scholars remove the space and refer to the mountain range as Hindukush.

The Hindu Kush (commonly understood to mean Killer of the Hindus or Hindu-Killer) is an 800-kilometre-long (500 mi) mountain range that stretches through Afghanistan, from its centre to Northern Pakistan and into Tajikistan. The range forms the western section of the Hindu Kush Himalayan Region (HKH) and is the westernmost extension of the Pamir Mountains, the Karakoram and the Himalayas.

It divides the valley of the Amu Darya (the ancient Oxus) to the north from the Indus River valley to the south. The range has numerous high snow-capped peaks, with the highest point being Tirich Mir or Terichmir at 7,708 metres (25,289 ft) in the Chitral District of Khyber Pakhtunkhwa, Pakistan.

To the north, near its northeastern end, the Hindu Kush buttresses the Pamir Mountains near the point where the borders of China, Pakistan and Afghanistan meet, after which it runs southwest through Pakistan and into Afghanistan near their border.

The eastern end of the Hindu Kush in the north merges with the Karakoram Range. Towards its southern end, it connects with the Spin Ghar Range near the Kabul River. The mountains have been associated with the legendary Alborz mountains of Iran in the Shahnameh.

The Hindu Kush range region was a historically significant centre of Buddhism, with sites such as the Bamiyan Buddhas. After the conquest by the Sunni Caliphate, a portion of the Hindu Kush known as Kafiristan remained a stronghold of polytheistic sects until the 19th century when it was renamed Nuristan (land of light) by the Durrani Emirate. The range and communities settled in it hosted ancient monasteries, important trade networks and travellers between Central Asia and South Asia.

The Hindu Kush range has also been the passageway during the invasions of the Indian subcontinent and continues to be important during modern-era warfare in Afghanistan.

Several other theories have been propounded as to the origins of the name the Hindu Kush. According to Nigel Allan, two alternate meanings, 'sparkling snows of India' and 'mountains of India', are also possible, with Kush being interpreted as a soft variant of the Persian Kuh ('mountain').

Allan states that, to Arab geographers, Hindu Kush was the frontier boundary where Hindustan started.

Other theories suggest that the word 'Hindu' in the Hindu Kush is derived from Sindhu, meaning 'river' in Sanskrit, while kush is a Sanskrit root related to Persian kūh, meaning 'mountain', or that the name may be from the ancient Avestan language, with the meaning 'water mountain'.

According to Hobson-Jobson, a 19th-century British dictionary, Hindukush might be a corruption of the ancient Latin Indicus (Caucasus); the entry mentions the interpretation first given by Ibn Batuta as a popular theory already at that time, despite doubts cast upon it.

Hindu Kush is generally translated as 'Killer of Hindu' or 'Hindu-Killer'. Boyle's Persian-English dictionary indicates that the suffix -koš [koʃ] is the present stem of the verb 'to kill' (koštan کشتن). According to linguist Francis Joseph Steingass, the suffix -kush means 'a male; (imp. of kushtan in comp.) a killer, who kills, slays, murders, oppresses as azhdaha-kush.'

The name may be a reminder of the days when slaves from the Indian subcontinent died in the harsh weather typical of the Afghan mountains while being taken from India to Turkestan. In his travel memoirs about Khorasan, the 14th-century Moroccan traveller Ibn Baṭṭuṭa mentioned crossing into India via the mountain passes of the Hindu Kush. In his Rihla, he states that the name of the mountain range translates to 'Hindu-slayer' due to slaves from India dying there:

After this I proceeded to the city of Barwan, in the road to which is a high mountain, covered with snow and exceedingly cold; they call it the Hindu Kush, that is Hindu-slayer, because most of the slaves brought thither from India die on account of the intenseness of the cold.

— Ibn Batutta, Chapter XIII, Rihla – Khorasan

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