Vishnuvardhana IV was the tenth king of the Eastern Chalukyas, which ruled the region of Vengi.
He had martial ties with the imperial Rashtrakutas.
The Rashtrakuta emperor Dhruva Dharavarsha gave his daughter, Silabhattarika, in marriage to Vishnuvardhana IV to forge an alliance with the Western Ganga Dynasty after defeating and humbling him in 784.
A concise history of Karnataka: from pre-historic times to the present.
A History of South India, OUP, New Delhi (Reprinted 2002).