[Bell Historians] Ringing bells backwards as a signal

[Richard Smith]

I'm sure we've all heard anecdotal accounts of bells being 
rung backwards, for example to signal an impending German 
invasion last century.

I've just come across two much older examples.

During the Civil War, in orders dated 2 Jan 1642/3, the 
Mayor of Wigan refers to the bells being rung backward as a 
signal in the event of an asault on the town.  [Wigan 
Archives, D/D An/Bundle 16/11]

During the Rising of the North, a letter possibly from 
Richard Lowther to the Earl of Westmorland dated 13? Nov 
1569 refers to the Earl of Northumberland having taken 
Topcliffe Bridge and ringing the bells backwards.  [Cal SP 
dom., Eliz. Add. 1566-79, p 105]

Richard