Green’s Dictionary of Slang

the watch (an early form of policing).

1612		Dekker O per se O L2: They were Roagues taken in Romboyles (that is to say, in Watches or Wards) by the Petty Harman Beck.
1648		Dekker ‘Canters Dict.’ in Eng. Villainies (9th edn) n.p.: Romboyle, watch and ward.
1665		Head Eng. Rogue I .
1674		Head Canting Academy (2nd edn) 178: Rumboyle A Ward or Watch.
c.1698		B.E. Dict. Canting Crew n.p.: Romboyles c. Watch and Ward.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Romboyles, watch and ward [...] Rumboyle.
1811		Lex. Balatronicum [as cit. 1785].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.