The area has been inhabited by Illyrian tribe of Dalmatae and Delminium was a town established by them in nowadays Tomislavgrad. Daelminium was situated on the location of today's Roman Catholic basilica, named after the first Croatian saint, Nikola Tavelić.
The area of Tomislavgrad has been populated in 4000 BC - 2400 BC, even before Illyrians arrived, and from that time only polished stone axes remained as proof that someone was here. Bronze Age (1800 BC - 800 BC) also left few marks in Tomislavgrad. Archeological collection of monastery in Široki Brijeg had few items founded on area of Tomislavgrad from Bronze Age: 34 bronze sickles, 3 axes and 2 spears. Those items were found in Stipanjići and Lug near Tomislavgrad. Those items were given to Archeological collection "fra Mijo Čuić and fra Stjepan Naletilić". Later, Fr Vojislav Mikulić found a bronze axe in Letka which he gave to those collections. Unfortunately, collection was destroyed in fire at the end of World War II. Only one sickle and axe survived the tragedy. However, this collection says that population of Tomislavgrad at the time worked in primary sector, they were cattlemen, farmers and warriors. Unlike their unnamed predecessors, Illyrians left material proofs from their time. On the slopes of the mountains which circle Tomislavgrad, Illyrians built 36 fortifications. These forts served as watchtower or forts against the enemy. There are also many graves of Illyrians which means that they cared about their dead. Same as forts, graves are dating from Bronze and Iron Age to Roman conquest of Delminium (Tomislavgrad). In the graves of dead Illyrians, jewellery and items which the dead used, were found.
Another inhabitants, except Illyrians, were Celts. They brought higher culture, crafts and most importantly better arms. But soon, Celts have been assimilated as Illirians, since there was only small number of them. As Romans conquered
