Indus Basin in the context of "South Asian"

South Asia is the southern subregion of Asia that is defined in both geographical and ethnic-cultural terms. South Asia, with a population of 2.04 billion, contains a quarter (25%) of the world's population. As commonly conceptualised, the modern states of South Asia include Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka, with Afghanistan also often included, which may otherwise be classified as part of Central Asia. South Asia borders East Asia to the northeast, Central Asia to the northwest, West Asia to the west and Southeast Asia to the east. Apart from Southeast Asia, Maritime South Asia is the only subregion of Asia that lies partly within the Southern Hemisphere. The British Indian Ocean Territory and two out of 26 atolls of the Maldives in South Asia lie entirely within the Southern Hemisphere. Topographically, it is dominated by the Indian subcontinent and is bounded by the Indian Ocean in the south, and the Himalayas, Karakoram, and Pamir Mountains in the north.

Settled life emerged on the Indian subcontinent in the western margins of the Indus River Basin 9,000 years ago, evolving gradually into the Indus Valley Civilisation of the third millennium BCE. By 1200 BCE, an archaic form of Sanskrit, an Indo-European language, had diffused into India from the northwest, with the Dravidian languages being supplanted in the northern and western regions. By 400 BCE, stratification and exclusion by caste had emerged within Hinduism, and Buddhism and Jainism had arisen, proclaiming social orders unlinked to heredity.

The Lower Himalayan Range, also called the Lesser Himalayas and Mahabharat Lekh or Himachal, is one of the four parallel sub-ranges of the Himalayas. It has the Great Himalayas to the north and the Sivalik Hills to the south. It extends from the Indus River Basin to the Brahmaputra Valley, traversing across Afghanistan, Pakistan, India, Nepal China and Bhutan. The sub-range has an average elevation of 3,700–4,500 m (12,100–14,800 ft).

Mu'izz al-Din Muhammad ibn Sam (Persian: معز الدین محمد بن سام, romanized: Muʿizz al-Dīn Muḥammad ibn Sām; c. 1144 – 15 March 1206), also known as Muhammad of Ghor or Muhammad Ghori, was a ruler from the Ghurid dynasty based in the Ghor region of what is today central Afghanistan who ruled from 1173 to 1206. Muhammad and his elder brother Ghiyath al-Din Muhammad ruled in a dyarchy until the latter's death in 1203. Ghiyath al-Din, the senior partner, governed the western Ghurid regions from his capital at Firozkoh whereas Muhammad extended Ghurid rule eastwards into South Asia, laying the foundation of Islamic rule in South Asia, which lasted after him for nearly half a millennium under evolving Muslim dynasties.

During his early career as governor of the southern tract of Ghurid Empire, Muhammad subjugated the Oghuz Turks after a series of forays and annexed Ghazni where he was installed by Ghiyath al-Din Muhammad as an independent sovereign. Expanding the Ghurid dominion east of the Indus Delta from his base in Ghazni, Muhammad crossed the river Indus in 1175, approaching it through the Gomal Pass and captured Multan and Uch from the Carmathians within a year. Afterwards, Muhammad took his army by the way of lower Sindh, endeavouring to penetrate into present-day Gujarat through the Thar Desert. However, he was wounded and his forces were routed near Mount Abu at Kasahrada by a coalition of Rajput chiefs led by the Chaulukya king Mularaja. This setback forced him to change his route for future inroads into the Indian Plains. Hence, Muhammad pressed his forces against the Ghaznavids and uprooted them by 1186, conquering the upper Indus Plain along with most of the Punjab. After expelling the Ghaznavids from their last bastion, Muhammad secured the Khyber Pass, the traditional route of entry for invading armies into northern India.

The Indian campaign of Alexander the Great began in 327 BC and lasted until 325 BC. After conquering the Achaemenid Persian Empire, the Macedonian army undertook an expedition into the Indus Valley of Northwestern Indian subcontinent. Within two years, Alexander expanded the Macedonian Empire, a kingdom closely linked to the broader Greek world, to include Gandhara and the Indus Valley of Punjab and Sindh (now in India and Pakistan), surpassing the earlier frontiers established by the Persian Achaemenid conquest.

Following Macedon's absorption of Gandhara (a former Persian satrapy), including the city of Taxila, Alexander and his troops advanced into Punjab, where they were confronted by Porus, the regional Indian king. In 326 BC, Alexander defeated Porus and the Pauravas during the Battle of the Hydaspes, but that engagement was possibly the Macedonians' most costly battle.

In ancient Greek geography the basin of the Indus River was on the extreme eastern fringe of the known world. The term "India" (Indikē in Greek) was used by Herodotus and later Greek writers in three different senses: the Achaemenid Persian province Hindush which was at the lower Indus basin (Sindh), the entire Indus land, which contained two other Persian provinces—Thatagush and Gandāra, and the whole of Indian subcontinent. The ethnic term "Indians" (Indoi) was most often used for Indians in the modern sense, represented by physical appearance and cultural markers such as wearing cotton, driving chariots and carrying iron-tipped arrows.