Plovdiv was given various names throughout its long history. It was originally a settlement by the name of Eumolpias, named after the mythical Thracian king Eumolpos. When Philip II of Macedonia conquered the area he renamed the city Philippoupolis. The Thracian name for the city, Pulpudeva, is a translation. After the Romans took control of the area, the city was named in latin :Trimontium, meaning the Three Hills. The slavic name occurred in different variants, Pəldin (Пълдин), Pləpdiv (Плъпдив) and Ploudin (Плоудин), based on the city’s later thracian name Pulpudeva, while the current variant Plovdiv was documented (as Пло(в)дївь) for the first time in a Bulgarian apocryphal chronicle of the 11th century. The city was known as Philippopolis in Western Europe well into the early 20th century. The city was known as Filibe in turkish during the Ottoman Empire and the name is still in use in Turkish.
Just like the city the river Maritsa (which is the longest river in Bulgaria) has changed names through the years. The oldest known name of the river is Rombus. In the antiquity it was also known as Habar, Hbrus, Evros,Ebrus,Marizo and its earliest mention as `Maritza` is in the 7th cencurywhere she is mentioned by the Byzantine historian Pahimer.