|Centuries:||1st century BC – 1st century – 2nd century|
|Decades:||60s 70s 80s – 90s – 100s 110s 120s|
|Years:||88 89 90 – 91 – 92 93 94|
|91 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||844|
|Chinese calendar||庚寅年 (Metal Tiger)
2787 or 2727
— to —
辛卯年 (Metal Rabbit)
2788 or 2728
|Coptic calendar||−193 – −192|
|- Vikram Samvat||147–148|
|- Shaka Samvat||13–14|
|- Kali Yuga||3192–3193|
|Iranian calendar||531 BP – 530 BP|
|Islamic calendar||547 BH – 546 BH|
|Minguo calendar||1821 before ROC
|Seleucid era||402/403 AG|
|Thai solar calendar||633–634|
Year 91 (XCI) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Glabrio and Traianus (or, less frequently, year 844 Ab urbe condita). The denomination 91 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.
- Manius Acilius Glabrio and Marcus Ulpius Traianus become Roman Consul.
- Pliny the Younger is named a tribunus plebis.
- The Chinese government reestablishes the Protectorate of the Western Regions.
Arts and sciences
- Julia Flavia, daughter of Roman Emperor Titus, lover of his brother Domitian (by forced abortion) (b. 64 AD)