Tangena in the context of Cardiac glycoside

Ranavalona I (born Rabodonandrianampoinimerina; 1778–16 August 1861), also known as Ramavo or Ranavalo-Manjaka I or Ranavalona reniny, was the sovereign of the Kingdom of Madagascar from 1828 to 1861. After positioning herself as queen following the death of her young husband Radama I, she pursued a policy of isolationism and self-sufficiency. She sought reduced economic and political ties with European powers and took vigorous measures to eradicate the small but growing Malagasy Christian movement initiated under Radama I by members of the London Missionary Society.

Ranavalona made heavy use of the traditional practice of fanompoana (forced labor as tax payment) to complete public works projects and develop an army. She had a standing army of between 20,000 and 30,000 Merina soldiers, whom she deployed to pacify outlying regions of the island and further expand the realm. The combination of regular warfare, slavery, disease, difficult forced labor and the practice of tangena (a harsh trial by ordeal using a poisonous nut from the Cerbera manghas tree) resulted in a high mortality rate among both soldiers and civilians during her 33-year reign, reducing Madagascar's population from 5 million in 1833 to 2.5 million in 1839.