Nearchus

Nearchus was the Admiral of the Fleet under Alexander the Great (336-323 BCE).
He is mentioned by Arrian in the Indica, which has a narrative of the sea voyage of Nearchus, and also has a description of the Culture, Geography and History of India.

In 334/3 BCE, Nearchus was appointed Satrap of newly conquered Lycia and Pamphylia.
Nearchus masterminded the Naval blockade of the Persian Fleets that led to the Fall of the Levant and Egypt.
In 328 BCE, Nearchus was sent to join Alexander in Afghanistan (Bactria).
In 326 BCE, Alexander built a Fleet on the Indus near Taxila, and appointed Nearchus as Admiral. The Fleet then sailed down the Indus, whilst the army followed along the shore.
In 325 BCE, Nearchus took between 17-20,000 men with the Fleet to explore the Persian Gulf. The journey is described in depth in Indica by Arrian.