Not much is known about this city but it was founded by Romans in 5 BC. However, ancient Greek, and later Roman maps clearly show that the area was populated by several native Illyrian peoples, including the Ardiaei, whom the ancient geographer Strabo lists as one of the three strongest Illyrian peoples – the other two being the Autariatae and the Dardani.
Capljina is situated in the wider Neretva valley region (the original homeland of ancient Illyrian people of Ardiaei), and its name derives from čaplja, which in former Serbo-Croatian language (nowadays divided into Bosnian/Croatian/Montenegrin and Serbian) means 'heron'. The Latin word for heron is ardea, a word that bears striking similarity with the name of Ardiaei, and it might possibly be its cognate. This theory opens up many possibilities for the interpretation of the original homeland of the Ardiaei and the etymology of their name. For example, heron might have had totemic pagan value among local Illyrians, due to its presence in this area, and it is not implausible to conclude that one of those Illyrian peoples named itself after a heron, the Ardiaei. The Latin word ardea might be a Latin translation of some original Illyrian word for 'heron' that Romans found when they settled in this area, or the 'ardea' itself, could have been an Illyrian word taken by Romans, who might have slightly altered it and integrated it into their language, the Latin. Indeed the word Ardiaei is found in ancient Greek sources predating the arrival of Romans and their language to the Illyrian lands. It is also possible that ancient Illyrians or Romans named this place 'the place of heron(s), and the Slavic settlers, who settled in the former Illyrian lands around 6th century A.D. translated the name of this place into their language(s), which in turn gave 'Čapljina', "the place of heron(s)".
In World War II, Ustase committed some of the most heinous atrocities in Čapljina and nearby villages. The town and the
