Year 398 BC was a year of the pre-Julian Roman calendar

Roman calendar

The Roman calendar changed its form several times in the time between the founding of Rome and the fall of the Roman Empire. This article generally discusses the early Roman or pre-Julian calendars...

. At the time, it was known as the Year of the Tribunate of Potitus, Medullinus, Lactucinus, Fidenas, Camillus and Cornutus (or, less frequently, year 356 Ab urbe condita

Ab urbe condita

Ab urbe condita is Latin for "from the founding of the City ", traditionally set in 753 BC. AUC is a year-numbering system used by some ancient Roman historians to identify particular Roman years...

). The denomination 398 BC for this year has been used since the early medieval period, when the Anno Domini

Anno Domini

and Before Christ are designations used to label or number years used with the Julian and Gregorian calendars....

 calendar era

Calendar era

A calendar era is the year numbering system used by a calendar. For example, the Gregorian calendar numbers its years in the Western Christian era . The instant, date, or year from which time is marked is called the epoch of the era...

 became the prevalent method in Europe for naming years.

Sicily

• Dionysius
  Dionysius I of Syracuse
  Dionysius I or Dionysius the Elder was a Greek tyrant of Syracuse, in what is now Sicily, southern Italy. He conquered several cities in Sicily and southern Italy, opposed Carthage's influence in Sicily and made Syracuse the most powerful of the Western Greek colonies...
  
  , tyrant
  Tyrant
  A tyrant was originally one who illegally seized and controlled a governmental power in a polis. Tyrants were a group of individuals who took over many Greek poleis during the uprising of the middle classes in the sixth and seventh centuries BC, ousting the aristocratic governments.Plato and...
  
   of Syracuse, breaks his peace treaty with Carthage
  Carthage
  Carthage , implying it was a 'new Tyre') is a major urban centre that has existed for nearly 3,000 years on the Gulf of Tunis, developing from a Phoenician colony of the 1st millennium BC...
  
   and strikes at Carthaginian cities in the western corner of Sicily
  Sicily
  Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
  
   which have been weakened by the plague. There is a massacre of Carthaginians in many of these cities. Motya
  Motya
  Motya , was an ancient and powerful city on an island off the west coast of Sicily, between Drepanum and Lilybaeum...
  
  , with its fine harbour, is attacked and captured.