The Mahābhārata (; , , ) is one of the two major Sanskrit epics of ancient India. The other is the Rāmāyaṇa. It tells if issues between two groups of cousins in the Kurukshetra Warm It also tells the fates of the Kaurava and the Pāṇḍava princes and their successors.

The Mahābhārata includes  philosophical and devotional material, It has a discussion of the four "goals of life" or puruṣārtha (12.161). The stories in the Mahābhārata include the Bhagavad Gita, the story of Damayanti, the story of Shakuntala, the story of Pururava and Urvashi, the story of Savitri and Satyavan, the story of Kacha and Devyani and the story of Rishyasringa. It also has a shortened version of the Rāmāyaṇa.

The Mahābhārata is normally said to be written by Vyāsa. Most of it was probably put together between the 3rd century BCE and the 3rd century CE. The oldest parts o it are not much older than around 400 BCE.  The text probably became in its final form by the early Gupta period (c. 4th century CE).

The Mahābhārata is the longest epic poem known.  It has been said to be "the longest poem ever written". Its longest version has over 100,000 śloka or over 200,000 individual verse lines.  It also has and long sections of prose. The Mahābhārata has about 1.8 million words in total. It is about ten times the length of the Iliad and the Odyssey combined, It is about four times the length of the Rāmāyaṇa. The importance of the Mahābhārata to world civilization has been compared to that of the Bible, the Quran, the works of Homer, Greek drama, or the works of William Shakespeare. It is sometimes called the fifth Veda.

Protagonists(weightage%)
Karna(35%)- Karna is the central protagonist of the Mahabharata written by Vyasa. The poem Jaya had been written mainly to commemorate Karna and Yudhisthira. He possessed all the qualities of his brother. Padmavati, wife of Karna is the main character of post-Kurukshetra Mahabharata. She was brought to Pandavas after the end of war.
Yudhisthira(14%) - Yudhisthira was considered the actual protagonist of the epic- Mahabharata after Karna. He was the king of the earth and the leader of successful Pandava team
Bhima(8%)-He killed the most number of enemies and villains of that era. He killed the 100 Kauravas, Jarasandha, Hidimba, Keechak etc. 
Arjuna+Nakula+Sahdev(8%)- He wad the rival of Karna(the protagonist of the epic). He was the listener of Bhagwada Gita.

Sage Vyasa taught this epic to his son Suka and his students Vaisampayana and others. King Janamejaya, the son of Parikshit and grandson of the heroes of the epic, performed a great sacrifice (yajna). The epic was retold by Vaisampayana to Janamejaya at the advice of Vyasa. Later on, the other sage Suta retold the Mahabharata similar to Vaisampayana to Janamejaya, to Saunaka and others, during a sacrifice performed by Saunaka in Naimisaranya, which is near Sitapur in Uttar Pradesh.

Parvas

Noted below are few words about the eighteen sections of the Mahabharata. In Mahabharata, these sections are called parvan. A parvan means a book. The names of all parvas or books of the Mahabharata are noted below.

Karna and the Pandavas 

When Yudhisthira got to know Karna was his eldest brother, he called Vedavyasa and heard the story of Karna from Narada. Narada narrated the story of Karna to Vedavyasa and 7 saptarishis along with Yudhisthira. The 7 saptarishis and 5 Pandavas went on and further sung glories of Karna in their kingdom. Yudhisthira commemorated Karna by naming the Ashwamedha horse- ShyamKarna. After the narration of Narada, Vyasa penned the "Jaya" epic keeping Karna and Yudhisthira as its central protagonists of 8800 shlokas. Vyasa narrated Mahabharata had been written to commemorate Karna's sacrifices and Yudhisthira's crowning as the king of earth.

Donation for it's compilation
In the year 1932, The Bhandarkar oriental research institute located in Pune, needed money for the compilation and publication of the Holy Mahabharata and a guest house. A formal request was made to the seventh Nizam of Hyderabad State, Mir Osman Ali Khan who in no time released a farman to donate Rs.1000 per year for a period of 11 years. 

Whereas, Rs. 50,000 was offered for the guest which is known as "Nizam guest house".

Related page 
 Manipur of Odisha

More information 
 Mahabharata Online - The Complete Translation of Vyasa Mahabharata and Stories from Mahabharata
 Some nice info on Hinduism including the Mahabharata

References

 
Hinduism
Hindu texts
National symbols of India