Decebalusatau "Yang Berani" (sebelumnya bernama Diurpaneus) adalah raja Dacia (87 – 106) yang terkenal karena bertempur dalam tiga peperangan melawan Romawi. Ia menegosiasikan interregnum perdamaian dengan Romawi sehingga kerajaan Dacia tetap ada. Setelah perdamaian disetujui, Decebalus terus bertindak sebagai raja yang independen dan bukan raja yang ditaklukan sehingga membuat Romawi kesal. Romawi kembali menyerang Dacia pada tahun 105 dan berhasil menjatuhkan Decebalus pada tahun 106. Ia akhirnya memilih bunuh diri.
^"De Imperatoribus Romanis"(Assorted Imperial Battle Descriptions). An Online Encyclopedia of Roman Emperors. Diakses tanggal 2007-11-08. Battle of Sarmizegetusa (Sarmizegetuza), A.D. 105. During Trajan's reign one of the most important Roman successes was the victory over the Dacians. The first important confrontation between the Romans and the Dacians took place in the year 87 and was initiated by Domitian. The praetorian prefectCornelius led five or six legions across the Danube on a bridge of ships and advanced towards Banat (in Romania). The Romans were surprised by a Dacian attack at Tapae (near the village of Bucova, in Romania). Legion V Alaude was crushed and Cornelius Fuscus was killed. The victorious general was originally known as Diurpaneus (see Manea, p.109), but after this victory he was called Decebalus (the brave one).
^ab"De Imperatoribus Romanis". Diakses tanggal 2007-11-08. In the year 88, the Romans resumed the offensive. The Roman troops were now led by the general Tettius Iulianus. The battle took place again at Tapae but this time the Romans defeated the Dacians. For fear of falling into a trap, Iulianus abandoned his plans of conquering Sarmizegetuza and, at the same time, Decebalus asked for peace. At first, Domitian refused this request, but after he was defeated in a war in Pannonia against the Marcomanni (a Germanic tribe), the emperor was obliged to accept the peace.
^"De Imperatoribus Romanis". Diakses tanggal 2007-11-08. Although the Dacians had been defeated, the emperor postponed the final siege for the conquering of Sarmizegetuza because his armies needed reorganization. Trajan imposed on the Dacians very hard peace conditions: Decebalus had to renounce claim to some regions of his kingdom, including Banat, Tara Hategului, Oltenia, and Muntenia in the area south-west of Transylvania. He had also to surrender all the Roman deserters and all his war machines. At Rome, Trajan was received as a winner and he took the name of Dacicus, a title that appears on his coinage of this period. At the beginning of the year 103 A.D., there were minted coins with the inscription: IMP NERVA TRAIANVS AVG GER DACICVS.
^"De Imperatoribus Romanis". Diakses tanggal 2007-11-08. However, during the years 103-105, Decebalus did not respect the peace conditions imposed by Trajan and the emperor then decided to destroy completely the Dacian kingdom and to conquer Sarmizegetuza.