Bohdan Khmelnytsky was a prominent Ukrainian leader and military commander in the 17th century. He is best known for leading the Ukrainian Cossacks in a rebellion against Polish rule, which began in 1648. This uprising, known as the Khmelnytsky Uprising, aimed to establish greater autonomy for Ukraine and improve the rights of the Cossacks. Khmelnytsky's efforts culminated in the signing of the Pereyaslav Agreement in 1654, which brought Ukraine under the protection of the Tsardom of Russia. His legacy is significant in Ukrainian history, as he is often regarded as a national hero who fought for Ukrainian independence and self-determination.