Atom Yarchanian, better known by his pen name Siamanto (15 August 1878 – August 1915), was an influential Armenian writer, poet and national figure from the late 19th century and early 20th century. He was killed by the Ottoman authorities during the Armenian genocide.

Yarchanian was born in 1878 in Agn, a town on the shores of the river Euphrates. He lived in his native town until the age of 14. He studied at the Nersesian School as a youth, where he developed an interest in poetry. The school's director encouraged him to continue developing his poetic talents. The director, Garegin Srvandztiants, gave him the name Siamanto, after the hero of one of his stories. Atom would use this name for the remainder of his life.

Siamanto came from a middle-upper-class family. They moved to Constantinople (Istanbul) in 1891, where he continued his studies at the Berberian School, graduating in 1896, during the Hamidian massacres. Like many other Armenian intellectuals, he fled the country for fear of persecution. He ended up in Egypt where he became depressed because of the butchery that his fellow Armenians had to endure.

In 1897, Siamanto moved to Paris and enrolled in literature at the Sorbonne. He was captivated by philosophy and Middle Eastern literature. He had to work various jobs while pursuing his studies because of his difficult financial situation. He developed many ties with well-known Armenian personalities in and outside Paris. He enjoyed reading in French and in Armenian, and read many of the best works of his time.

From Paris he moved to Geneva, and contributed to the Droshak newspaper, the organ of the Armenian Revolutionary Federation. His first poetic works were published in this newspaper under such headlines as "Heroically" (Armenian: Դիւցազնօրէն) and "The Knight’s Song" (Armenian: Ասպետին Երգը). The paper detailed the destruction of his homeland, was highly critical of the Ottoman government, and demanded equal rights for Armenians and more autonomy. Siamanto joined the cause and truly believed in an Armenia free of Ottoman oppression.^[2] Henceforth, many of his works and poems were highly nationalistic.

Siamanto fell ill in 1904, coming down with a case of pneumonia. He was treated at a hospital in Geneva and eventually fully recovered. For the next four years, he lived in various European cities such as Paris, Zurich, and Geneva. In 1908, along with many other Armenians, he returned to Constantinople after the proclamation of the Ottoman Constitution. However, in 1909, the Ottoman government made it clear that they were not safe by perpetrating the Adana massacre. Siamanto was once again deeply affected by the bloodshed. These events led him to write his most noted work, Bloody News from my Friend.

In 1910, he moved to the United States as an editor of Hairenik newspaper. After a year, he returned to Constantinople. In 1913 he visited Tiflis. On his way to his destination, he visited many landmarks associated with Armenian culture and history, including Mount Ararat, Khor Virap and Ejmiadzin.

He was one of the Armenian intellectuals tortured and killed by the Ottomans in 1915 during the Armenian genocide.