According to the historian Sen, Someshvara I's rule was a "brilliant period" in the history of the Western Chalukyas that would reach its zenith under Vikramaditya VI.
According to the historian Sastri, Rajadhiraja defeated Someshvara I in the battle of Dannada ("Dhanyakataka") on the banks of the Krishna River compelling the Western Chalukya armies to retreat, and the fort at Kollipakki (Kulpak) was razed to the ground.
However, according to Sastri, the Cholas were able to convert defeat into victory when their crown prince Rajendra II (brother of Rajadhiraja) mounted a surprise counterattack and pushed the Chalukya armies back.
Rajendra II crowned himself on the battlefield, mounted a victory pillar at Kollapura (modern Kohlapur) and returned to his capital Gangaikondacholapuram with much booty which including the Chalukya queens Sattiyavvai and Sangappai.
Hostilities continued and in c.1059 Rajendra Chola II invaded the Chalukya kingdom but was defeated on the banks of the Tungabhadra River.
[5][6][9][10] Politics of succession erupted again over the Vengi throne in c.1061 after the death of the Eastern Chalukya King Rajaraja Narendra.
On this occasion, Someshvara I had sent two armies, one under his general Chamundaraya and another into Gangavadi (southern Mysore territory) under his sons prince Vikramaditya VI and Jayasimha.
In the east he counted on the Nagavamsi ruler Dharavarsha and the Eastern Ganga dynasty King Vajrahasta II of Kalinga as his allies.
Unable to recover from his illness, Someshvara I committed ritual suicide (paramayoga) by drowning himself in the Tungabhadra river at Kuruvatti (modern Bellary district) on 29 March 1068.
[5][10][11][12] During this time of constant conflict with the Cholas, according to Kamath and Sastri, Someshvara I dealt successfully with the Shilaharas of the North Konkan, the Seuna (Yadava) dynasty King Bhillama III, the Paramara dynasty King Bhoja of Dhara, the Chaulukyas of Gujarat and the Pratiharas of central India.
[11][13] According to the historian Tripathi, toward the end of his reign, under the leadership of his brilliant son Vikramaditya VI, Someshvara I's armies marched east with an eye on the Gangetic plains.
The Chalukya armies marched further east, overwhelming the Kalachuri King Lakshmikarna of Madhyadesha and getting the better of the kingdoms of Mithila, Magadha, Anga, Vanga and Gouda.