Revenue stamps are stamps used to designate collected taxes and fees. They are issued by governments, national and local, and by official bodies of various kinds. They take many forms and may be gummed and ungummed, perforated or imperforate, printed or embossed, and of any size.
[From Wikipedia]
A little background first:
South Africa was officially the Union of South Africa until May 31, 1961, when it gained independence from the United Kingdom and became the Republic of South Africa. The currency system for the Union of South Africa was changed a few months prior, on Feb. 14, 1961.
On this day, the South African pound was replaced by the rand at a rate of one £SA = two Rand.
My sets of revenue stamps from South Africa for the periods 1954-60 (when it was still the Union of South Africa) and 1961-68 (the Republic of South Africa) are almost complete.
(Several other sets of revenue stamps were issued, but South Africa stopped using revenue stamps altogether in 2009).
Revenue stamps are similar to the postage stamps issued in South Africa during this time: printed on watermarked and gummed paper sheets, perforated and with increasing denominations in the set.
A big difference:
the highest denomination for a postage stamp issued for the time was
10 shillings (1954-60) or
R1 (1961-68),
while the highest denomination of a revenue stamp issued for the same period was
£100 (1954-60)— 200 times more, or
R200 (1961-68)— also 200 times more !
A reminder: in the old British currency system (and in South Africa’s), there were 12 pennies to a shilling, and 20 shillings to a pound.
Then I realized they are conversions of the penny, shilling and SA pound denominations from the 1954-60 set of revenue stamps into Rand:
R 1.25 for 12 shillings 6 pence,
R 1.50 for 15 shillings,
R2 for 1 pound, and
R4 for 2 pounds.
At the bottom is the Latin phrase EX UNITATE VIRES, formerly used as the national motto of South Africa. It was originally translated as “Union is Strength” but was later revised in 1961 to mean “Unity is Strength”.
Finally, right below the UNITATE is a tiny 57 printed in green, the year of issue of this particular stamp (1957).