|Millennium:||1st millennium BC|
|25 BC by topic|
|Gregorian calendar||25 BC|
|Ab urbe condita||729|
|Ancient Greek era||188th Olympiad, year 4|
|Balinese saka calendar||N/A|
|Chinese calendar||乙未年 (Wood Goat)|
2672 or 2612
— to —
丙申年 (Fire Monkey)
2673 or 2613
|Coptic calendar||−308 – −307|
|Ethiopian calendar||−32 – −31|
|- Vikram Samvat||32–33|
|- Shaka Samvat||N/A|
|- Kali Yuga||3076–3077|
|Iranian calendar||646 BP – 645 BP|
|Islamic calendar||666 BH – 665 BH|
|Julian calendar||25 BC|
|Minguo calendar||1936 before ROC|
|Seleucid era||287/288 AG|
|Thai solar calendar||518–519|
102 or −279 or −1051
— to —
103 or −278 or −1050
Year 25 BC was either a common year starting on Wednesday, Thursday or Friday or a leap year starting on Wednesday or Thursday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a leap year starting on Tuesday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Silanus (or, less frequently, year 729 Ab urbe condita). The denomination 25 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
- Imperator Caesar Augustus becomes Consul for the ninth time. His partner is Marcus Junius Silanus.
- The temple to Neptune on the Circus Flaminius is built.
- Estimation: Rome, capital of the Roman Empire becomes the largest city of the world, taking the lead from Chang'an, capital of China.
- Galatia becomes a Roman province after the death of its king. The Roman troops stationed there were relocated to Egypt.
- The Roman colony of Emerita Augusta was founded, which is present-day Mérida.
- The government gives its tributary states 20,000 rolls of silk cloth and about 20,000 pounds of silk floss.
- Rosenberg, Matt. "What Were the Largest Cities Throughout History?". ThoughtCo.