Dacian Wars refers to punitive expeditions (2) or wars of conquest (2) by the Roman Empire along its Danube River frontier against the north bank kingdom of Dacia and the Dacian king Decebalus, and the non-specific name will mean one of either:

• Domitian's Dacian War--The two punitive expeditions mounted as a border defense against raids of Moesia‎ from Dacia in 86-87 AD ordered by the Emperor Titus Flavius Domitianus (Domitian) in 87 AD, and 88 AD. The first expedition was an unmitigated disaster, and the second achieved a peace, seen as unfavorable and shameful by many in Rome.
  
  

• Trajan's Dacian Wars--The two campaigns of conquest ordered or led by the Emperor Trajan in 101-102 AD, and 105-106 AD from Moesia‎ across the Danube north into Dacia. Trajan's forces were successful in both cases, reducing Dacia to client state status in the first, and taking the territory over in the second.
  
  Roman conquest of Dacia stands at the base of the origin of Romanians.