SOME FAMOUS WARS OF INDIAN HISTORY:
THE CARNATIC WARS:
The First Carnatic War (1746 – 48) – 
Causes : The rivalry of the trading companies reached its climax with the arrival of Dupleix as theFrench Governor of Pondicherry in 1742. He wanted to strengthen the French position. It was at that time the Austrian War of Succession broke  out in Europe. England and France took opposite sides in that war. The  war echoed in India too. The English started the war against the French  in 1746.
Events : The English captured the French ships in the Indian waters with the help of Commodore Barnett. Dupleix appealed for help to the French Governor of Mauritius La Bourdonnais. The  French fleet came and blockaded Madras Port. With the joint efforts of  Dupleix and La Bourdonnais Madras was captured. Anwar-ud-din sent a huge  army under Mehpuzkhan to restore Madras. But it was defeated by a small  disciplined French force at the Battle of Adyar. Dupleix tried  to capture Fort St. David, but failed. Meanwhile the Austrian War of  Succession ended in Europe. The English and the French stopped their  fight in India.
Results : The Treaty of Aix-la-Chapelle, concluded in 1748, put an end to the Austrian War of Succession. The first Carnatic war also stopped. As per the treaty, Madras was given back to the English company in exchange of Louisburg in  North America to France. The First Carnatic War demonstrated that a  small group of disciplined soldiers, regularly paid, using guns, newly  developed in Europe, could easily defeat a much larger number of  soldiers of the Indian rulers.
The Second Carnatic War (1750 – 1754) : Though  the enmity between the French and the English ended in Europe, their  rivalry continued in India. The success of Dupleix against the Nawab’s  forces made him more confident and ambitious. Dupleix aimed to promote  the French interests. He began to fit one Indian ruler against the  other. The English were cautious and alarmed of the growing French  influence.
Causes : The Nizam of Hyderabad died in 1748. There arose a war of succession between Nasir Jung, the second son of the departed ruler and Mussafar Jung, his grandson. In the Carnatic Chanda Sahib, son-in-law of Dost Ali, claimed the throne of Arcot against Anwar-uddin. Mussafar  Jung and Chanda Sahib joined together and sought the French help. Nasir  Jung and Anwar-ud-din got the English help. Thus
the disputes for the throne of Hyderabad and Arcot became the cause for the war.
Events : The armies of Mussafar, Chanda Sahib and the French defeated Anwar-ud-din at Ambur in 1749. Anwar lost his life in the battle. His son Muhammed Ali escaped  to Tiruchirapalli for safety. He surrendered to the English. Chanda  Sahib became the Nawab of the Carnatic. He rewarded Dupleix’s help by  giving Valudanoor, Villianoor and Bahur near Pondicherry.  Then he marched towards Tiruchirapalli to capture Muhammed Ali. The  English came to the rescue of Muhammed Ali. Robert Clive, an army officer of the English East India Company, suggested a plan to attack Arcot. The English Governor Saunders accepted  it. He sent an army with Robert Clive and Major Lawrence. Clive  captured Arcot without any serious opposition in 1751. The French forces  and Chanda Sahib were defeated at Arni and Kaveripakkam.
Chanda  Sahib surrendered and he was beheaded in 1752. Dupleix failed to  capture Tiruchirapalli. He was recalled to France in 1754. With his  recall the second Carnatic war came to an end. The French were however  strongly entrenched at Hyderabad. Nasir Jung lost Robert Clive his  life in an encounter in 1750. Muzaffar Jung became the Nizam and amply  rewarded the French. The capture of Arcot was the most remarkable  achievement of the English in Carnatic war. Clive was hailed as the Hero of Arcot.
Results : In 1755, the Treaty of Pondicherry was  signed. French possessions were given back to the French. The English  emerged as the winners in the Carnatic region. Whereas in Hyderabad the  French general Bussy maintained a steady ascendancy of the French.
The Third Carnatic War (1758 – 1763) 
Causes : The out-break of the Seven Years War in Europe was the immediate cause for the Third Carnatic War. The French Government sent Count-de-Lally as  the Governor and commander-in-chief of French possessions in India.  Soon after his arrival in India, he attacked and captured Fort.St. David. With  a view to capture Chennai, he recalled Bussy, the French General from  Hyderabad. That was a great blunder. As soon as Bussy left Hyderabad,  the English conquered the Northern Circars. Salabat Jung, the Nizam of Hyderabad was forced to change sides. The French lost their political influence in Hyderabad. The French generals Lally and Bussy were decisively defeated by the English. The French even surrendered Pondicherry in 1761.
Results : The Third Carnatic War came to an end in 1763 by the Treaty of Paris. According to the terms of the treaty, Pondicherry, Karaikal and  other French possessions were returned to the French on condition that  they should not fortify them. The Third Carnatic war put an end to the  French ambition in India.
Causes for the success of the English : 
(1) The English had a much better financial position compared to the French, 
(2) The British Government rendered adequate support to the company which was not given by the French Government,
(3) The English had acquired better trade facilities compared to the French,
(4) England had a very strong and superior naval power than the French, 
(5) There was good understanding between the English Generals,
(6) Peace prevailed in England and hence they concentrated more on their affairs in India and 
(7)  Dupleix, an able Governor, was recalled when his services were very  much required in India and his successor was not as efficient as  Dupleix.
Battle of Plassey (23 June 1757 ):
Causes : Siraj-ud-daulah prevented the English from fortifying Fort William. The English refused to stop the new fortification. So he attacked their factory at Cassim Bazar. He
captured  Fort William. Many prominent Englishmen escaped. But one hundred and  forty six English were taken as prisoners. They were said to have been  kept in a very small room. It is said that on 20 June 1756 hundred and  twenty three of them died out of suffocation. Only twenty three  survived. The English historians describe this incident as the Black Hole Tragedy.
This incident made the English at Chennai to send a relieving force under Robert Clive along with Admiral Watson to Bengal. Clive entered into a conspiracy with Mir Jafar, the Commander-in-Chief of Siraj-ud daulah.
Events : Clive marched towards Plassey, on 23 June 1757 which was near to the Nawab’s capital Murshidabad. As  agreed earlier, Mir Jafar, the Chief commander of Siraj-ud-daulah, did  not take up arms against the English army. On the other hand Nawab’s  soldiers fled from the battlefield. Later the Nawab was killed and Mir  Jafar was
made the Nawab of Bengal as promised by Clive. The Battle of Plassey was  merely a skirmish. But in its results it was one of the most decisive  battles in Indian History. The battle paved the way for the foundation  of the English rule in India.
Results : The English acquired a large sum of money from the new Nawab. The English company got the territory of the 24 Parganas. Mir  Jafar became a puppet in the hands of Clive. He had no powers. He could  not satisfy the demands of the English. So he was forced to resign in  1760. Then his son-in-law Mir Kasim was appointed as the Nawab of Bengal. In course of time, he also could not satisfy the growing demands of the English.
Battle of Buxar (1764): 
Causes : Mir Kasim was an young, energetic and ambitious ruler. He wanted to be independent. He shifted his capital to Monghyr, a  place far away from Kolkata. He also employed foreign experts to train  his army. So a quarrel broke-out between him and the English. The  English decided to overthrow him. It resulted in the Battle of Buxar in 1764. The combined armies of Mir Kasim, Shuja-uddaulah, the Nawab of Oudh, and the Mughal Emperor Shah Alam II were defeated by the English General Major Munro. Mir Kasim fled from the battle and the other two surrendered to the English. 
Results : The battle came to an end with the Treaty of Allahabad, concluded  in 1765. As per the treaty, the Province of Oudh was returned to  Shuja-ud-daulah. But he had to pay a war loss of Rs.50 lakhs to the  English. The districts of Kara and Allahabad were given to Shah Alam.  Shuja-ud-daulah was forced to maintain English troops for the defence of  his state. Shah Alam granted the Diwani Right of Bengal, Bihar and Orissa to  the English. In turn, the English agreed to pay him a pension of rupees  26 lakhs per year. The Battle of Buxar made the English virtually the  masters of Bengal. It also proved their military superiority and  unchallenged power. As a result of his success in Bengal, Robert Clive  was appointed as the first Governor of Bengal (1758 – 1760). He consolidated the British power both in Bengal and in the Deccan. He introduced a new
administrative system in Bengal called Dual or Double Government.  The administration of Bengal was carried on by two powers. The Nawab of  Bengal was a nominal head. But the real power was exercised by the  English.
THE MYSORE WARS:
First Mysore War (1767 – 1769) : 
Causes : Hyder  Ali strengthened his army by including the French soldiers into his  service. He extended his territories by conquering many areas in South  India. The rapid rise of Hyder Ali naturally excited the jealousy of the  Marathas, the Nizam of Hyderabad and the English. They joined  together and formed a triple alliance and declared a war on Hyder Ali.  By his diplomacy, Hyder Ali, cleverly won over the Marathas and the  Nizam. But under the leadership of the English General, Smith, Hyder Ali was defeated at Changam and Tiruvannamalai in 1767. At the same time, Tippu Sultan, son of Hyder Ali advanced towards Chennai. So the English were forced to enter into an agreement.
Results : The war ended by the Treaty of Madras (Chennai) in 1769. Territories
conquered during the war were restored to each other. The English agreed to help
Hyder Ali in case of attack by his enemies, the Nizam and the Marathas.
Second Mysore War (1780 – 1784) : 
Causes : Mysore  was attacked by the Marathas in 1771. As per the treaty of Madras, the  English did not help Hyder Ali. So Hyder Ali got angry. He wanted for an  opportunity to strike at the English. When Mahe, a French  possession in the dominion of Hyder Ali was attacked by the English,  Hyder Ali declared war on the English in 1780. He defeated the English  force in the Carnatic. He made them surrender. Hyder Ali occupied almost  the
whole of the Carnatic. But the English, under Sir Eyre Coote, defeated Hyder Ali at Porto Novo in  1781. In the meantime, Hyder Ali died of cancer in 1782. But his son  Tippu Sultan continued the war with the English for two more years.
Results : The war came to an end with an agreement signed in 1784, called the Treaty of Mangalore. Both  the sides agreed to exchange the captured territories and war  prisoners. Thus the Second Mysore War came to an end without any  tangible results.
Third Mysore War (1790-92):
Lord Cornwallis (1786-1793)  became the Governor General of Bengal in 1786. He was also made  Commander-in-Chief of the English army. He fought against Tippu in the  Third Mysore war.
Causes : The  English started improving their relationship with the Nizam and the  Marathas. Tippu, on the other hand, improved his resources. He got the  Frenchhelp. He attacked Travancore in 1789 which was a friendly  state of the English. So Cornwallis declared a war on Tippu in 1790.  Both the troops had victories and defeats alternately. The war came to  an end in 1792.
Results : Tippu signed the Treaty of Srirangapatnam with the English. He had to give half of his kingdom to the English. The English got Malabar, Coorg, Dindugal, and Baramahal (now the Salem and Erode areas). Tippu was compelled to pay a huge war
indemnity  of over three crore rupees. He had to surrender two of his sons as  hostages to the English until he paid the indemnity. 
The Fourth Mysore War (1799): 
Causes : The  Treaty of Srirangapatinam failed to bring peace between Tippu and the  English. Tippu refused to accept the subsidiary alliance of Lord  Wellesley. He wanted to take revenge on the English. He sent emissaries  to Kabul, Constantinople, Arabia and France to get their  support. When Wellesley came to know all about Tippu’s activities, he  declared war at once against him in 1799. Tippu suffered defeats at the  hands of General Stuart and General Harris. Wellesley himself besieged Srirangapatinam. Tippu fought bravely but died in the battle.
Results : The English annexed large portions of Mysore. The central part of Mysore was given to Krishna Raja of Wadiar dynasty. Tippu’s family was removed from  Srirangapatinam and sent to Vellore prison.
THE MARATHA WARS:
First Maratha War (1776-82): 
During the administration of Warran Hastings (1772 – 1785) the First Maratha War was fought. In 1772, Madhava Rao, the Peshwa of the Maratha Kingdom died. He had no issue. His younger brother Narayana Rao succeeded to the throne. But his ambitious uncle Raghoba alias Raghunath Rao murdered him. He announced himself as the next Peshwa. Nana Fadnavis, a senior and loyal statesman objected to it. He wanted to make Madhva Rao Narayanan, the son of Narayana Rao, as the next Peshwa. Raghoba went to the English for help. He signed a treaty in 1775, known as the Treaty of Surat, with the Governor of Bombay. By this treaty, Raghoba agreed to handover the islands of Salsette and Bassein to the English in return for their help to get the Peshwaship. This was done without the knowledge of the Governor-General, Warren Hastings and he rejected the treaty. Nana Fadnavis signed a treaty called the Treaty of Purandhar in 1776 with the English. Thus Nana Fadnavis raised his position and defeated Raghoba. The war ended with the signing of the Treaty of Salbai in 1782.
Results : Madhava Rao Narayanan became the Peshwa. The English returned the territories except Salsette. Raghoba was granted a pension of three lakhs rupees a year.
The Second Maratha War (1803 – 06):
Causes : The great Maratha statesman Nana Fadnavis died in 1800. After his death war brokeout among the Maratha chiefs, Bhonsle and Sindhia. Peshwa  Baji Rao II was a weak ruler. He sought the help of the English for  protection. The English defeated the combined armies of Scindia and  Bhonsle.
Results : Both the Scindia and the Bhonsle entered into subsidiary system. The Maratha power was gradually weakened.
The Third Maratha War (1817 – 1818) :
Causes : In  1817, Peshwa Baji Rao II tried to organize a confederacy of Maratha  chiefs against the English. When an envoy was killed by his minister,  Baji Rao II was asked to sign a humiliating treaty. He refused to do so  and declared war on the English. But he was defeated by the English. By  this success Lord Hastings the Governor-General, established British Supremacy in India.
Results : The  power of the Peshwa was shattered beyond recovery. All the Maratha  chiefs were reduced to a subordinate position under the English. The  Maratha efforts to save India from the English had failed. Baji Rao II  was given an annual pension of 8 lakh rupees. Mumbai (Bombay) Presidency was  formed with this region. According to historian Marshman, the results  of the Maratha wars subdued not only the native armies but also the  native minds. The English themselves raised Pratab Singh a descendant of
Chatrapathi Shivaji to Satara, but he also remained a small subordinate ruler of the English.
Causes for the decline of the Marathas : 
1) Internal weakness of the Marathas,
 2) Lack of political sagacity, 
3) Incapable leadership, 
4) Feudal organization 
5) Weakness in the social organization of the Marathas,
 6) Neglect of economic affairs of the state and 
7) The superior diplomatic skill and spy system of the English.