The ceremony took place on Tuesday and was attended by Polish historical reenactors dressed as Hussar cavalrymen, including one portraying Sobieski.
The event was hosted by Patryk Jaki, a Polish MEP from the right-wing opposition Law and Justice (PiS) party and co-chair of the European Conservatives and Reformists group in the European legislature.
Jaki said Sobieski was a symbol of "stopping the Islamisation" of Europe and defending Christian values. He also argued that more Polish symbols should be present in the European Parliament.
The reenactors arrived on horseback wearing historical clothing and armour from the reigns of Sobieski and King Stephen Báthory, Polish state news agency PAP reported.
They carried historical weapons, including sabres, koncerz swords and lances, while the horses were equipped with period cavalry saddles.
The group also brought a replica of Sobieski's royal banner, featuring a white eagle on a red background, and a Hussar officers' tent decorated with white-and-red Hussar crosses.
Jaki said efforts to name the room after Sobieski had taken several years.
Sobieski was king of Poland and grand duke of Lithuania from 1674 until his death in 1696. He is best known for his role in the 1683 Battle of Vienna, when allied forces defeated the Ottoman army besieging the city.
Polish Hussars, also known as "winged horsemen," played a major role in the battle, including in the famous cavalry charge.
The elite heavy cavalry was known for the large wings attached to their backs, which were intended to intimidate the enemy during a charge.
(sp/gs)
Source: PAP