E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A relic of the Roman Confarreatio, a mode of marriage practised by the highest class in Rome. It was performed before tèn witnesses by the Pontifex Maximus, and the contracting parties mutually partook of a cake made of salt, water, and flour (far) Only those born in such wedlock were eligible for the high sacred offices.