Why Were Dates Put On Coins?

To sum up the "why" question in a single word, the answer is "tradition". Although even today, governments can control the currency by issuing edicts and laws commanding the withdrawal of coins of certain dates - such as happened in Germany for the 2 mark coin dated 1951. But for the most part, the only people who know or care about the dates on coins these days are coin collectors.

As to the question of "when", dates on coins only appeared sporadically on coins up until the 1500s - as can be seen by our "how far back can we go" thread, it gets harder and harder to find dated coins for particular years the further back you go. Coins with AD dates, in particular, are a relatively recent innovation; the AD date first appeared on a coin of Denmark in 1234 - the date took up the entire legend on both sides of the coin: ANNO DOMINI and MCCXXXIIII. Apparently they thought the date had numerological significance worth dedicating an entire coin to.

Dates using other calendars go back much further. The Islamic series has a near-continuous date stream going back to Year 70 (AD 689). The Muslims copied the concept from the Sassanian Persians they had conquered; Persian/Sassanian dated coins can go back to the AD 200s, and various regnal-year and city-founding calendars can be found on coins going as far back as the 200s BC. Perhaps the most famous city-founding calendar is the Roman anno urbis conditae calendar; however, it was rarely used at all on Roman coins, which are either undated, dated by the years of office-holding of the emperor, or (in the case of Republic-era coins) dated in the Roman fashion by naming the two people who had been elected Consuls for that year.

Two issues, really.

1. The coin was too similar in design, size and overall appearance to the 1 mark. There was pressure to withdraw it anyway, even before the incident outlined at #2 was discovered.

2. Dies for the 1951-G 2 mark coin were misappropriated by a mint official and used to strike an unknown number of unauthorized coins - counterfeits, though struck with genuine dies.

The 1951 2 mark coin is the only Federal Republic of Germany coin that can not still be redeemed and exchanged for the equivalent value in euros.

You are *such* an optimist.

Actually, Australia now dates all of it's banknotes.
The serial number on all of the notes consists of two letters and eight digits, instead of six.
The first two digits of the eight digit number are the year in which the note was printed.

Cool! Thanks!

Great educational info there Sap.
You mentioned coins with dates as far back as the 200's BC. Did they really have BC on them?