Year 277 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 Consulship of Rufinus and Brutus (or, less frequently, year 477 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 277 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.

Greece

• Antigonus
  Antigonus II Gonatas
  Antigonus II Gonatas was a powerful ruler who firmly established the Antigonid dynasty in Macedonia and acquired fame for his victory over the Gauls who had invaded the Balkans.-Birth and family:...
  
   crosses the Hellespont and defeats the Celt
  Celt
  The Celts were a diverse group of tribal societies in Iron Age and Roman-era Europe who spoke Celtic languages.The earliest archaeological culture commonly accepted as Celtic, or rather Proto-Celtic, was the central European Hallstatt culture , named for the rich grave finds in Hallstatt, Austria....
  
  s under the command of Cerethrius near Lysimachia
  Lysimachia (Thrace)
  Lysimachia was an important Hellenistic Greek town on the north-western extremity of the Thracian Chersonese in what is now the European part of Turkey, not far from the bay of Melas .- History :...
  
   at the neck of the Thracian Chersonese
  Thracian Chersonese
  The Thracian Chersonese was the ancient name of the Gallipoli peninsula, in the part of historic Thrace that is now part of modern Turkey.The peninsula runs in a south-westerly direction into the Aegean Sea, between the Hellespont and the bay of Melas . Near Agora it was protected by a wall...
  
  . After this success, he is acknowledged by the Macedon
  Macedon
  Macedonia or Macedon was an ancient kingdom, centered in the northeastern part of the Greek peninsula, bordered by Epirus to the west, Paeonia to the north, the region of Thrace to the east and Thessaly to the south....
  
  ians as their king.

Sicily

• Pyrrhus
  Pyrrhus of Epirus
  Pyrrhus or Pyrrhos was a Greek general and statesman of the Hellenistic era. He was king of the Greek tribe of Molossians, of the royal Aeacid house , and later he became king of Epirus and Macedon . He was one of the strongest opponents of early Rome...
  
   captures Eryx
  Eryx (Sicily)
  Eryx , was an ancient city and a mountain in the west of Sicily, about 10 km from Drepana , and 3 km from the sea-coast...
  
  , the strongest Carthaginian
  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...
  
   fortress in 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,...
  
  . This prompts the rest of the Carthaginian-controlled cities in Sicily to defect to Pyrrhus.