Indiction

Indiction, a cycle of 15 years instituted by Constantine the Great, and which began on the 24th September 812, the day of his victory over Maxentius; to find the indiction of any year add 1 and divide by 15.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

India-rubber, Caoutchouc * Indium
India
India
Indian Civil Service
Indian Mutiny
Indian Ocean
Indian Territory
Indiana
Indianapolis
Indians, American
India-rubber, Caoutchouc
Indiction
Indium
Individualism
Indo-China
Indo-European
Indo-Germanic
Indore
Indra
Induction
Indulgence
Indus