Lake Constance (German: Bodensee); A shadow between Germany, Switzerland and Austria. Konstanz is based on the alpine Pre Alp Mountains. There are 273 km long and 536 square kilometers of the coast of Lake Balaton in Hungary with a surface area (594 square kilometers) and Lake of Geneva in Switzerland (582 square kilometers) after the third large lake in Central Europe. It contains 48 km³ of water and 89 km³ of Lake Geneva and then Central Europe is the second largest lake.
The lake consists of three parts: the Obersee (Upper lake), Untersee (Lower lake) and the Seerhein (Rhine lake) which connects with the Rhine. In the vicinity of the lake, Bavaria and Baden-Württemberg provinces in Germany, Vorarlberg province in Austria and Thurgau, St. Petersburg in Switzerland. Gallen and Schaffhausen cantons
About 10,000 years ago, after the end of the last ice age, Obersee and Untersee were connected. With the Upper Rhine becoming extinct to erosion, the lake level gradually descended and the Konstanz pit appeared. Both lakes were known by different names in antiquity, and then a common name began to be used for unknown reasons.
Roman geographer Pomponius Mela, is the first source mentioned the lake, BC 43 Oberss to Lacus Venetus, Untersee is known by the name Lacus Acronius. Nature researcher Gaius Plinius Secundus was ancestor of Lacus Raetiae Brigantinus in the entire Lake Constance in 75 BC. Brigantium most important centers around the lake at that time (Bregenz) and of the origin of the city is based on the Celtic tribe that settled here Brigantium. Ammianus Marcellinus uses the name Lacus Brigantiae for the lake. 
The word Bodensee, used as the German name for the lake, comes from a place called Bodman. The Bodman was said to be Bodamon in Old High German.  Located in the western end of the lake there was a royal palace in the early Middle Ages in this region belong to Frank, who was a duke region of Alamar and also there was a mint. Thus the lake was able to give the German name. 
After the formation of the Council of Constance in the 15th century, a new name for the lake began to be used: Lacus Constantinus.  Constantine, who gave the name of Şehire, is Constantine Chlorus, not his first Constantine, who gave his name to Istanbul. In some languages the term “Bodensee” was used (nl Bodenmeer, Boden, Bodenberg, Bodenjärvi, Bodenjärvi, Bodenjärvi, Bodenjärvi, Litt Bodenezers, Bodenjers, russ. Боденское озеро , poln Jezioro Bodeńskie, tschech Bodamské jezero, slowak Bodamské jazero, ung Bodeni-tó, bulg Боденско езеро, ukr Боденське озеро, kroat Bodensko jezero, alban Liqeni i Bodenit, aserbaidschan Boden, tatarisch Боден күле, marathi बोडन से Bodene sē, mandarin 波登 湖 / 博登 湖, Bódēng-hui, cor. 보덴 호 Boden-ho, japan. ボ ー デ ン 湖 Boden-putting.) in some languages, “Constance lake” name was chosen. (frz.Lac de Constance, ital.Lago di Costanza, port.Lago de Constanza, span.Lago de Constanza, rumän.Lacul Constanţa, griech.Aίμνη της Κωνσταντίας – Limni tis Konstantias, arab بحيرة كونستانس buħaira Konstans, lake)
It is also seen that some ancient writers, such as Tacitus, use the Swabian name for the lake. However, this also causes some confusion. The Romans used Svabia in the form of Mare Suebicum for the Baltic Sea, not for Lake Constance. The reason for this was that the Süevler, a Germanic tribe, had settled on the shores of the Baltic Sea. 
There was no trace of settlement from the Old Stone Age around the lake, because during this period the lake was completely covered by the Rhine. The finds from the Middle Stone Age (8000-5500 BC) they wander around the community of hunters and gatherers, but shows that settlement. It’s just the camping tracks. In the middle and late periods of the Polished Stone Age, settlements on the lake side and pile-based houses begin to emerge. This remains were particularly encountered in Überlinger See, Konstanzer Bucht and Obersee. In Unteruhldingen, a pile of pile-based houses was reconstructed and used today as a museum. Findings from the Iron Age belonging to the Hallstatt culture have been preserved because most of them are below the forest area. From the end of the Iron Age it is understood that the Celtics are located on the banks of the lake. From 450 BC, traces belonging to the cultures of La Tene are rarely seen. At the end of this period written documents about the lake region begin to emerge. The inhabitants of the lake are Helvetler in the south, Raetians in the Rhine Valley, and Vindictors in the Kuzetday. The most important settlements around the lake are Bregenz (croatian Brigantion) and today’s Konstanz.
During the reign of Augustus and Tiberius, the lake was bound to Rome through campaigns held in 15/25 BC to capture the Alps. In these times a small lake battle took place at 15 BC. The most important settlement during the Romans period was Bregenz and a marine fleet was built here. The Romans also settled in Lindau, but since the coasts are in the swamps,