E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Each English archer carries twelve Scotchmen under his girdle. This was a common saying at one time, because the English were unerring archers, and each archer carried in his belt twelve arrows (Sir Walter Scott: Tales of a Grandfather, vii.).
The Twelve. All the prelates of the Roman Catholic Church. Of course the Twelve Apostles.
The Pope identifies himself with the Master, and addresses those 700 prelates as the Twelve.The Times, December 11, 1869.