Why has this woman become symbolic to Sudanese protesters?

Video of a woman leading chants in anti-government protests in the capital of Sudan, Khartoum, has been shared hundreds of thousands of times on Twitter.

She has been dubbed "Kandaka", which means Nubian queen.

The protesters are calling for the resignation of President Omar al-Bashir who has been accused of human rights abuses and allowing political corruption.

Since protests began in December, 38 people have died, according to government officials. Human Rights Watch says the number is higher.