Jílové was probably founded as a settlement on an ancient trade route from Bohemia to Lusatia. The nearby Lotarův vrch mountain may already had been the site of the 1126 Battle of Chlumec between Duke Soběslav I of Bohemia and King Lothair III of Germany, whose exact location is unknown. The first written mention of Jílové (under the name "Eulow") is from 1384 in a deed issued by Emperor Charles IV.