The world in 104 BC — what happened that year

8 events the sources record for this year, grouped by region.

What happened

The Taichu calendar was adopted: the first month became the start of the year, yellow was set as the color, five as the number, and official titles and musical pitches were fixed. (Book of Han (Hanshu), Imperial Annals 漢書卷006 武帝太初元年五月)
Li Guangli conscripted convicts from across the empire and set out west to campaign against Dayuan. (Book of Han (Hanshu), Imperial Annals 漢書卷006 武帝太初元年八月)
When fire broke out at the Bailiang Terrace, following Yongzhi's advice, he built a grander Jianzhang Palace with a thousand gates and ten thousand doors, with models of Taiye Pond and the immortal islands Penglai, Fangzhang and Yingzhou. (Records of the Grand Historian (Shiji), Annals 史記卷012 孝武本紀)

General Kammahatthaka subdued Kalatanaga in the capital, but his younger brother Vattagamani killed him and became king. (Mahavamsa (Great Chronicle of Sri Lanka) 33.33-34) tradition
Five months after Vattagamani took the throne, the Brahmin Tissa of Rohana rebelled; seven Tamils landed at Mahatittha and demanded the king's parasol. (Mahavamsa (Great Chronicle of Sri Lanka) 33.37-40) tradition

Aristobulus is the first to wear the diadem; after killing his mother and brother, he dies within a year (Josephus, Jewish War and Antiquities of the Jews BJ 1.70–71)
Aristobulus puts on the crown and imprisons his mother and brothers (Josephus, Jewish War and Antiquities of the Jews 13.301)

On the first of January Marius holds his second consulship and triumph (Plutarch's Parallel Lives Plut. Marius 12.2)