(Tagli delli Soldi 4 per Lettera)
From 1609 through 1797, the Republic of Venice required that all notaries, scribes, and public agents sending letters to government agencies had to pay 4 soldi per letter. The funds were turned over to the office of water commissioners to control tidal flooding. Accordingly, the sheets bore the letters AQ (Acque or waters) along with the lion of St. Mark, the symbol of Venice. The charge was accounted for through the use of numbered AQ lettersheets (tagli delli soldi 4 per lettera). The lettersheets were privately printed and distributed by a "daziere" or revenue officer. The AQ sheets could be used as a wrapper enclosing the letter, or the message could be written directly on the sheet.
In addition to the letters AQ and the lion of St. Mark, the lettersheets had text providing that, by order of the Most Illustrious Elders and Managers of the Waters, noting the decision of their Excellencies on 12 November 1608 setting a Fee of 4 soldi per Letter, each Chancellor of a State Office undertakes not to respond or take any action in the future regarding any letter unless each letter is enclosed in or written on one of these stamped and numbered sheets. The text also provides for a fine of 100 ducati for violations.
The AQ lettersheets are considered by many to be the world's first postal stationery. However, others consider the AQ lettersheets to be a type of revenue (fiscal) paper. Finally, some consider the AQ lettersheets to be semi-postal in nature, due to the use of the revenue for flood relief.
Over the nearly 200 years that the AQ lettersheets were used, there were many variations in the names of the revenue officers, valid dates, imprints of the lion, and dates of validity. For simplicity, the AQ letter sheets can be divided into 10 categories.
The 4 soldi charge was not marked on the AQ lettersheets. However, the lettersheets were recorded on the postal carrier "Polizza Di Viaggi" [waybill], such as the one illustrated above. The AQ lettersheets are the "Lettere Pubbliche" [official letters]. The waybill records a round trip from Venice to Giuidal di Bellun, modern day Belluno. The other categories on the waybill are Lettere Bianche [unpaid letters], Pieghi da Oncia N. Onze [letters one ounce or over], Lettere per Strada [way letters], Lettere per Stati Esteri [foreign letters], Lettere Franche [paid letters], and Lettere su Tramessi [letters accompanying goods].
Anthony Belfiore, "Saving Venice -- Philatelically: An Historical Overview" in Fiftieth American Philatelic Congress (Abbot Lutz, ed. 1984).
Giorgio Dal Gian, I Timbri Postali ed i "Tagli Delli Soldi 4 Per Lettera" Della Repubblica di Venezia (1950).