Foreverness indicates that at the time of writing (1970) Vance was in Athens. [ref]

First publication was in The Magazine of Fantasy and Science Fiction, July and August 1972. [ref]

First book publication in 1973 by Dell Publishing. [ref]

Foreverness indicates that at the time of writing (1970) Vance was in Ireland. [ref]

The first publication in The Magazine of Fantasy and Science Fiction (February and March 1971) involved a version that was shorter than the novel. (ref: colophon Durdane, 1976 Meulenhof)

The first book publication was as The Anome in 1973 by Dell Publishing. [ref]

The first publication in French was also serialized (in three parts, 1973). [ref]

Plot intro from Wikipedia:

It tells the story of a boy growing to manhood in the land of Shant, a society composed of many different, and wildly individual cantons, some of which are run by cults. Each adult wears an explosive torc which can be detonated by remote command, bringing about instant death by decapitation. The torcs are controlled by an anonymous dictator, the Anome, whose identity is literally unknown. Because those whose heads are exploded are selected primarily by the cantonal leaders, for violations of local law, the Anome is able to operate with only a handful of assistants, or ‘Benevolences’, who themselves do not know his identity. (accessed 7 March 2019)