Made from an offshoot of the Tree of the Knowledge of Good and Evil in the Garden of Eden, the wood takes various forms across the millennia, becoming an object of reverence, desire and fear for various crowned heads until the early seventh century, when a Christian emperor humbly carries it to its sanctuary in Jerusalem.

WSJ: A Heavenly View From On High | Basilica of Santa Croce | Agnolo Gaddi | By Francis X. Rocca

It is an offshoot of the parent organisation, in the US, which emerged in 1986 from a research project at the University of San Francisco.

BBC: Silver surfers brave the net

To find out, Kelly ordered a briefing book from some high-toned outfit like the Economist Intelligence Unit (EIU), an offshoot of The Economist magazine.

FORBES: The CIA For Everyman