According to the Ramayana, Rama is the seventh avatar of Vishnu while Lakshmana, Bharata and Shatrughna are considered as part-incarnations of Sheshanaga, Shankha and Sudarshan Chakra respectively.
Bharata was born to the virtuous king of Ayodhya, Dasharatha and his second wife, Queen Kaikeyi. He was married to Mandavi, daughter of Kushadhwaja, Janaka's younger brother. Thus, Mandavi was Sita's cousin. They had two sons - Taksha and Pushkala.
According to Valmiki Ramayana the four sons of king Dasharatha i.e. Rama, Lakshmana, Bharata and Shatrughna were very close to each other. Ram was in line to become the king of Ayodhya, as dictated by Primogeniture policy followed in the Ikshvaku clan, which they belonged to. But, Bharat's mother Kaikeyi, before the crowning of Rama went into Kopa Bhawan. The Kopa Bhawan was a place where the wives of the ruling king could go when they felt neglected, in order to compel the king to come visit her and hear her complaints. When king Dasharatha arrived, she reminded him of the two wishes he had offered to her when she had saved his life in a battle. For her first boon, she asked for the exile or Vanvas of Rama for 14 years. Her second wish was to make her son Bharata, the second in line to throne, the heir apparent. Since the clan of Raghu ( as the Ikshavaku clan is also called ) was known for keeping their word, Dasharatha had no choice but to adhere to her wishes. Once the order was officially announced, Rama went to exile with his wife Sita and younger brother Lakshmana. Bharata was visiting his maternal relatives, and on returning a few days later, heard the news of his elder brother's exile and his crowning as the heir apparent. Due to the bond shared between the brothers, he became angry with his mother Kaikeyi and her maid Manthara, who had sown the seeds of discord in Kaikeyi's mind. As King Dasharatha lay on his death bed, he cried for his eldest son Rama. On his death, Bharata along with the mothers and Shatrughna went to meet Rama and requested him to come back. When Rama refused to dishonor his father's word, Bharata asked for his sandals. He then placed the footwear on the royal seat of Ayodhya, thus laying clear the fact that Ram was the de facto ruler of Ayodha, and Bharata would only rule in his stead, for the time he wasn't there. In the 14 years that followed, he went to Nandigrama (forest near Ayodhya) to pray to gods for his brother's safe arrival, living in austere conditions and leaving the amenities of the royal palace. There, he survived by eating only kanda mul and wearing the rough clothes of rishi munis or hermits. After 14 years, Rama was reunited with him and they went back to Ayodhya. There, Rama was crowned the king.