"The first example of untouchability is seen after Islam came," Gopal said at a book release event here on Monday.
"It is seen when at Raja Dahir's household his queens were on way to commit 'johar'. They mentioned the word 'malechcha' and said they need to hurry to the 'johar', else the 'malechcha' will touch them and they will become impure.
"This is the first example of untouchability in Indian text," Gopal said.
The word 'Dalit' was coined by the British with a view to "divide and rule", he added.
The RSS Sah-karyavah also spoke on Islamic invasion and religious conversion. He accused both Islam and Christianity of taking the conversion route to expand their numbers.
Union Culture Minister Prahlad Patel was on stage when Gopal made the comments.
But JD(U)'s General Secretary Pawan Kumar Verma said it was more important to look within than blame others.
Taking a dig at Gopal, Verma said that it was not the ethos of Hinduism to blame its problems on others. The JD(U) is an ally of the BJP, whose ideological mentor is the Rashtriya Swayamsewak Sangh (RSS).
Earlier, RSS chief Mohan Bhagwat sparked a row by calling for a debate between people who favour and oppose reservation in jobs and education.
A comment on similar lines before the Bihar Assembly elections in 2015 triggered outrage, contributing to the BJP's defeat.
( With inputs from IANS )