(1621–1626), Lakshmi Narayan's son and successor, was a pleasure-loving ruler who failed to exert his authority to levy taxes on the king of Bhutan. In his peaceful reign, he sponsored schools for the aristocracy and supported intellectuals. His successor Pran Narayan (1626–1665) ruled in peace until 1657, when a struggle for succession in the Mughal empire began between Aurangzeb and his brothers. Pran Narayan invaded Bengal. However, by this time Aurangzeb had consolidated his power and sent his armies to invade Bihar and Assam. Pran Narayan retreated to the mountains and waged a guerrilla war for three years, finally making a pact with the Mughal Nawab Shaista Khan in 1664. During his rule, the Behar kingdom expanded to Tajhat Baharband Pargana in the south, Basakpur near Khutaghat of Goalapara district in the east and Bhatgaon within Morang in the west. Thus Koch Bihar maintained some of its sovereignty Maharaja Pran Narayan rebuilt the temples of Baneswar, Shandeswar and the Kamteswari temple of Gosanimari. He sent for architects from Delhi to complete the Jalpesh temple, but the work was not completed in his lifetime. He constructed broad highways and bridges, and many beautiful buildings in his capital. He was a patron of the arts. Madan Narayan or Mod Narayan (1665–1680) succeeded Pran Narayan after a short struggle with his brothers. For some time, the power behind the throne was Mahi Narayan, who had been Nazir (summoner) for his father. After a fierce struggle, Madan Narayan gained control and Mahi Narayan fled to Bhutan. Madan Narayan began a survey of his lands and a register of landholdings. He completed the construction of the Jalpesh Shiva temple, providing lands for the temple's maintenance. Conflict with Bhutan and Tibet (1680–1772) The growing power of Bhutan saw the turmoil in Behar and the waning authority of the Mughals as an opportunity to extend their influence and control. They provided support to competitors for the throne of Koch Bihar, and later attempted outright annexation. On the death of Madan Narayan with no immediate successor, the sons of the Nazir Mahi Narayan attacked Behar, assisted by the Bhutan army. The Raikats of Baikunthapur, distant relatives of the royal family based in the Jalpaiguri area, sent troops and helped force the Bhutia army to retreat. The Raikats crowned Basudev Narayan (1680–1682), Madan Narayan's brother, as Maharajah and helped establish peace before returning to their home. Two years later,