E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A corruption of Crabat or Croät. It was introduced into France by some French officers on their return from Germany in 1636. The Croäts, who guarded the Turkish frontiers of Austria, and acted as scouts on the flanks of the army, wore linen round their necks, tied in front, and the officers wore muslin or silk. When France organised a regiment on the model of the Croäts, these linen neckcloths were imitated, and the regiment was called The Royal Cravat.
The Bonny Cravat. A public-house sign at Woodchurch, Kent; a corruption of La bonne corvette. Woodchurch was noted for its smuggling proclivities, and the Bonnie Cravat was a smugglers hostelry.