E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Bishop, Cardinal, Pope (as beverages):
Bishop is made by pouring red wine (such as claret or burgundy), either hot or cold, on ripe bitter oranges. The liquor is then sugared and spiced to taste. In Germany, bishop is a mixture of wine, sugar, nutmeg, and orange or lemon. It is sometimes called Purple Wine, and has received its name of bishop from its colour.
Cardinal is made by using white wine instead of red.
Pope is made by using tokay.
When I was at college, Cup was spiced audit ale; Bishop was cup with wine (properly claret or burgundy) added; Càrdinal was cup with brandy added. All were served with a hedge-hog [i.e. a whole lemon or orange bristling
with cloves] floating in the midst. Each guest had his own glass or cup filled by a ladle from the common bowl (a large silver one).
The bishop hath put his foot in it. Said of milk or porridge that is burnt, or of meat over-roasted. Tyndale says, If the podech be burned-to, or the meate ouer rosted, we saye the byshope hath put his fote in the potte, and explains it thus, because the bishopes burn who they lust. Such food is also said to be bishopped.