Porus in the context of "Battle of the Hydaspes"

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.

The History of Punjab is the history of the Punjab region which is a geopolitical, cultural, and historical region in the northwest of South Asia, comprising the Punjab province in Pakistan and the Punjab state in India. It is believed that the earliest evidence of human habitation in Punjab traces to the Soan valley of the Pothohar, between the Indus and the Jhelum rivers, where Soanian culture developed between 774,000 BC and 11,700 BC. This period goes back to the first interglacial period in the second Ice Age, from which remnants of stone and flint tools have been found.

The Punjab region was the site of one of the earliest cradle of civilizations, the Bronze Age Harrapan civilization that flourished from about 3000 B.C. and declined rapidly 1,000 years later, following the Indo-Aryan migrations that overran the region in waves between 1500 and 500 B.C. The migrating Indo-Aryan tribes gave rise to the Iron Age Vedic civilization, which lasted till 500 BC. During this era, the Rigveda was composed in Punjab, laying the foundation of Hinduism. In the 6th century BC, Pushkarasarin, the monarch of Gandhara, assumed a role in halting the expansionary ambitions of the Achaemenid Empire until during the reign of Darius wherein tribute rendered by Gandhara to him is first documented. A century later, the Janapadas of Punjab encountered the expansive undertakings of Alexander. The Janapadas exhibited resistance to his advances, notably the Aśvaka of Gandhara, the Mallians of South Punjab, and Porus of Central Punjab. Following the demise of Alexander, Chandragupta Maurya, who had received his education in the city of Taxila, garnered support from republics such as Trigarta and Gandhara. He subsequently conquered the Nanda Empire, with Taxila being designated as the provincial capital of the Northwestern territories. After its decline, the Indo-Greeks, Indo-Sakas and Indo-Parthians successively established reigns in Punjab however other states maintained autonomy and other janapadas such as that of the Yaudheya and the Audumbaras in Eastern Punjab resisted their expansions. In the late 1st century AD the Kushan Empire annexed Punjab, Gandharas cultural zenith occurred during this period in which artwork from the region flourished.

The Pauravas were an ancient tribe in the northern Indus valley, to which Raja Porus may have belonged.

Boukephala (Ancient Greek: Βουκεφάλα) and Nikaia (Νίκαια) were two cities founded by Alexander the Great on either side of the Hydaspes (modern-day Jhelum River, Pakistan) during his invasion of the Indian subcontinent. The cities, two of many founded by Alexander, were built shortly after his victory over the Indian king Porus at the Battle of the Hydaspes in early 326 BC.

It is not certain which settlement had which name. Built on the site of the battlefield, the city on the eastern bank was most likely called Nikaia (from nike, lit. 'victory'), while its western companion was probably named after Alexander's horse Bucephalus, who died during or after the battle. Their construction was supervised by Craterus, one of Alexander's leading generals. Both cities initially suffered from the rains of the South Asian monsoon. Boukephala seems to have had a more distinguished legacy than Nikaia: mentioned by Pliny the Elder and Ptolemy, it appears in the 1st-century AD Periplus Maris Erythraei manuscript and on the later Tabula Peutingeriana map. The cities' precise locations are unknown, but it is considered likely that Boukephala was located in the vicinity of modern Jalalpur and that Nikaia was across the river near present-day Mong.