When refuting charges of delays in the post, he claimed:-
"A stamp is invented, that is putt upon every letter shewing the day of the moneth that every letter comes to this office, so that no letter Carryer may dare to detayne a letter from post to post ; which, before, was usual."
Bishop published the announcement of the "Bishop Mark" in the Mercurius Publicus. The Bishop Marks varied in size and in lettering, and they remained in general use until 1787 with survivals into 1788.
Some excellent examples of Bishop Marks can be seen on Eunice Shanahan's website.
With 2011 being the 350th anniversary of Bishop's Mark, Royal Mail has produced a striking generic smilers sheet showing more than 20 different types of postmark that have been used in Britain across the centuries. The sheet will be on sale from 15 September (including at Autumn Stampex).
This is the first Generic sheet (since the one issued in January 2010 which introduced the design) to use the 'wax seal' 1st class stamp introduced in February 2010 as part of the Business Customised Sheet range. It is not available for Personalisation as a Smiler stamp. The labels show:
Column 1: Bishop Mark 1661, Essex Post (1674), Dockwra (1680), Birmingham 'Chandelier' (1772), and Provincial Penny Post (Aylsham, Norfolk).
Column 2: Red Maltese Cross (1840), Barred Numeral England & Wales (1844), Pearson Hill machine (1857), Duplex - International Exhibition (1862), and Edinburgh duplex, Brunswick Star (1863)
Centre of Sheet: Britain's Most Northerly Post Office, Baltasound (permanent pictorial handstamp, in use currently), Britain's most southerly post office, The Lizard Helston Cornwall (counter datestamp),
the Oldest post office in Britain, Sanquar, Dumfries-shire (permanent pictorial handstamp - now closed), Longest placename in postmark, Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch (special handstamp for re-opening of railway station).
Column 3: Birmingham Squared Circle (1879), Scottish Double Arc, Largs (1883), Parcel Post 'Label' Handstamp Cannon Street London (1887), First machine slogan, War Bonds (1917), and First Tourist Slogan, Hastings (1963).
Column 4: First Day of Issue handstamp, Stratford-upon-Avon (1964 - Shakespeare), National Postal Museum Handstamp (1969), Self-Inking Datestamp [SID] Winchester (1981 counter date stamp), First regular ink-jet slogan Watford (1997), and Travelling Post Office operational handstamp, last day of service (Midland TPO South No2 Side 9 Jan 2004).
Click here for larger image, and here for super-size (1.1Mb) image.
Update: Special postmarks for the date of issue are shown here.