Letter sheet

Recent academic research and conservation initiatives have termed such folded and sealed letters as "letterpackets”;[1] however, only a relatively small number of early examples, such as the Brienne Collection (1689–1706) at The Hague,[2] are known to exist.

Most countries' postal authorities have issued true lettersheets at some stage; however, most have discontinued their use, except in the form of an aerogram, due to the popularity of envelopes.

New South Wales issued prepaid lettersheets in 1838 with uninked embossed stamps (making them difficult to see) to prepay postage within the town of Sydney.

[5] The design incorporated Britannia at the centre top with a shield and a reclining lion surrounded on either side by a representation of the continents of Asia and North America with people reading their mail in the two lower corners.

These lettersheets, predominantly showing bird's-eye views and street scenes, were created to comply with, yet circumvent, postal regulations that, like the United Kingdom's, were based on the number of sheets of paper.

These lettersheets were popular because of their 8.5 × 21 inch size that could be folded in half, providing four pages for writing but the Post Office regarded them as one sheet of paper.

He personally copyrighted the product in February 1933 and it was used first in Iraq and later in the British Mandate of Palestine where Gumbley was in charge of postal matters in the late 1930s.

Allied POW communications through the Red Cross used a special lettersheet inscribed Prisoner of War Air Mail in English and German or Japanese with a 2½d indicia.

Towards the end of WWII, at least eight forged German Feldpost lettersheets were printed by the OSS Operation Cornflakes to undermine Axis morale during late 1944 and 1945.