Some context: Joshua Lawrence Chamberlain (born Lawrence Joshua Chamberlain, September 8, 1828 - February 24, 1914) was an American college professor from the State of Maine, who volunteered during the American Civil War to join the Union Army. He became a highly respected and decorated Union officer, reaching the rank of brigadier general (and brevet major general). He is best known for his gallantry at the Battle of Gettysburg, for which he was awarded the Medal of Honor. Chamberlain was commissioned a lieutenant colonel in the 20th Maine Volunteer Infantry Regiment in 1862 and fought at the Battle of Fredericksburg.
Chamberlain became most famous for his achievements during the Battle of Gettysburg. On July 2, the second day of the battle, Union forces were recovering from initial setbacks and hastily regrouping into defensive positions on a line of hills south of the town. Sensing the momentary vulnerability of the Union forces, the Confederates began an attack against the Union left flank. Chamberlain's brigade, commanded by Col. Strong Vincent, was sent to defend Little Round Top by the army's Chief of Engineers, Brig. Gen. Gouverneur K. Warren. Chamberlain found himself and the 20th Maine at the far left end of the entire Union line. He quickly understood the strategic significance of the small hill, and the need for the 20th Maine to hold the Union left at all costs. The men from Maine waited until troops from the 15th Regiment Alabama Infantry, commanded by Col. William C. Oates, charged up the hill, attempting to flank the Union position. Time and time again the Confederates struck, until the 20th Maine was almost doubled back upon itself. With many casualties and ammunition running low, Col. Chamberlain recognized the dire circumstances and ordered his left wing (which was now looking southeast, compared to the rest of the regiment, which was facing west) to initiate a bayonet charge. From his report of the day: "At that crisis, I ordered the bayonet. The word was enough." While battlefield conditions make it unlikely that many men heard Chamberlain's order, most historians believe he initiated the charge.  The 20th Maine charged down the hill, with the left wing wheeling continually to make the charging line swing like a hinge, thus creating a simultaneous frontal assault and flanking maneuver, capturing 101 of the Confederate soldiers and successfully saving the flank. This version of the battle was popularized by the book The Killer Angels and the movie Gettysburg, but there is debate on the historical validity of this account. Chamberlain sustained two slight wounds in the battle, one when a shot hit his sword scabbard and bruised his thigh, and another when his right foot was hit by a spent bullet or piece of shrapnel. Chamberlain also personally took a Confederate prisoner with his saber during the charge. After initiating the maneuver, he came upon a Confederate Officer wielding a revolver who quickly fired, narrowly missing his face. Chamberlain remained steadfast, and with his sword at the officer's throat accepted the man's arms and surrender. The pistol Chamberlain captured at Gettysburg can still be seen on display in the Civil War exhibit of the Maine State Museum. For his tenacity at defending Little Round Top, he was known by the sobriquet Lion of the Round Top. Prior to the battle, Chamberlain was quite ill, developing malaria and dysentery. Later, due to this illness, he was taken off active duty until he recovered.  For his "daring heroism and great tenacity in holding his position on the Little Round Top against repeated assaults, and carrying the advance position on the Great Round Top", Chamberlain was awarded the Medal of Honor.
What position did he hold in the military?
A: 

Some context: The Vedic period or Vedic age (c. 1500 - c. 600 BCE) is the period in the history of the Indian subcontinent intervening between the end of the urban Indus Valley Civilization, and a second urbanisation which began in c. 600 BCE. It gets its name from the Vedas, which are liturgical texts containing details of life during this period that have been interpreted to be historical and constitute the primary sources for understanding the period. The Vedas were composed and orally transmitted by speakers of an Old Indo-Aryan language who had migrated into the northwestern regions of the Indian subcontinent early in this period. The associated Vedic culture was tribal and pastoral until c. 1200 or 1100 BCE, and centred in the Punjab.
After the 12th century BCE, as the Rigveda had taken its final form, the Vedic society transitioned from semi-nomadic life to settled agriculture. Vedic culture extended into the western Ganges Plain. Possession of horses remained an important priority of Vedic leaders and a remnant of the nomadic lifestyle, resulting in trade routes beyond the Hindu Kush to maintain this supply as horses needed for cavalry and sacrifice could not be bred in India. The Gangetic plains had remained out of bounds to the Vedic tribes because of thick forest cover. After 1000 BCE, the use of iron axes and ploughs became widespread and the jungles could be cleared with ease. This enabled the Vedic Aryans to settle at the western Gangetic plains. Many of the old tribes coalesced to form larger political units.  The Vedic religion was further developed when the Indo-Aryans migrated into the Ganges Plain after c. 1100 BCE and became settled farmers, further syncretising with the native cultures of northern India. In this period the varna system emerged, state Kulke and Rothermund, which in this stage of Indian history were a "hierarchical order of estates which reflected a division of labor among various social classes". The Vedic period estates were four: Brahmin priests and warrior nobility stood on top, free peasants and traders were the third, and slaves, labourers and artisans, many belonging to the indigenous people, were the fourth. This was a period where agriculture, metal, and commodity production, as well as trade, greatly expanded, and the Vedic era texts including the early Upanishads and many Sutras important to later Hindu culture were completed.  The Kuru Kingdom, the earliest Vedic "state", was formed by a "super-tribe" which joined several tribes in a new unit. To govern this state, Vedic hymns were collected and transcribed, and new rituals were developed, which formed the now orthodox Shrauta rituals. Two key figures in this process of the development of the Kuru state were the king Parikshit and his successor Janamejaya, transforming this realm into the dominant political and cultural power of northern Iron Age India.  The most well-known of the new religious sacrifices that arose in this period were the Ashvamedha (horse sacrifice). This sacrifice involved setting a consecrated horse free to roam the kingdoms for a year. The horse was followed by a chosen band of warriors. The kingdoms and chiefdoms in which the horse wandered had to pay homage or prepare to battle the king to whom the horse belonged. This sacrifice put considerable pressure on inter-state relations in this era. This period saw also the beginning of the social stratification by the use of varna, the division of Vedic society in Kshatriya, Brahmins, Vaishya and Shudra.  The Kuru kingdom declined after its defeat by the non-Vedic Salva tribe, and the political centre of Vedic culture shifted east, into the Panchala kingdom on the Ganges. Later, the kingdom of Videha emerged as a political centre farther to the East, in what is today northern Bihar of India and south eastern Nepal, reaching its prominence under the king Janaka, whose court provided patronage for Brahmin sages and philosophers such as Yajnavalkya, Uddalaka Aruni, and Gargi Vachaknavi.
how did the society change
A:
the old tribes coalesced to form larger political units.