Chazal identify coins were minted picturing an old man and woman on one
side - Rashi (Bava Kama 97b) explains Yitzchak and Rivka, and Avraham and
Sara [this must have been AFTER Avraham A begged HKBH to differentiate him
from his son - until then they looked like identical twins]
Also note they minted the couples rather than the men on one side and the
women on the other - UNLESS they had a Mechitzah between them!!
Does it say anywhere that the coins were made in their era?
It quotes a tannaitic statement about a Matbeia shel Yerushalayim and a
Matbeia shel Avraham Avinu and what they looked like. Since Avraham is
on the coin, a "coin of Avraham" is only telling you what's on the coin,
not who owned or coined it. The names fit the descriptions.
Why would Chazal have a statement about these matbei'os? Perhaps they were
privately minted medalions, and thus an interesting middle case between
state-minted kesef usable for machatzis hasheqel and a plain boring asimon.
Really, I don't know.
The Avraham coin is a list of "monitin" in Bereishis Rabba 39 https://www.sefaria.org/Bereishit_Rabbah.39.11 , the Y-m coin is not.
"Monitin" is from the same shoresh as the English words "mint" and
"monetary", but may also be related to monument, because the meaning of
"fame" or "reputation" took over the original etymology. Which is why
went with "medalion".
Either way, these coins / medalions also aren't particularly described
as the contemporary with the person they honor.
Reb Micha asked; Does it say anywhere that the coins were made in their era?
It seems that the Medrash understands that the coins were minted in his
lifetime, indeed, even early in his lifetime, when he was tested to leave
his father's house.
See Rashi beginning Lech LeCha - travelling A] disrupts family life, B] it
reduces one's wealth and C] lessens one's renown. Therefore these three
blessings - children, wealth and a sterling reputation, neutralised them
all (Genesis Rabbah 39:11)
The Medrash Yulkut describes this minted coin as fulfillment of HKBHs
promise - I WILL MAKE YOU FAMOUS, one of those three blessings, designed to
neutralise the expected negative effects of leaving ones home and trying to
settle in a new place.
There does not seem to be much point in offering a band-aid many years
AFTER the Makka, that will not help address the trouble associated with
leaving home. I suppose one might say that he was so famous that even many
years later he was commemorated with a minted coin.
BTW leaving home in those days [less so these days when the first Q asked
is Funn Vannent Kumt a Yid? it is the equivalent of a diplomat presenting
credentials - Ah so you must know so and so - which is a politely veiled
message that we can find out all about you, you have no secrets from us.]
When no one knows you, who will trust you? Who will offer you any credit?
Everyone is thinking why would a sane person leave a comfortable life and
risk so much. Is he an axe murderer? What is he running away from?
The Medrash Yulkut describes this minted coin as fulfillment of HKBHs
promise - I WILL MAKE YOU FAMOUS, one of those three blessings, designed to
neutralise the expected negative effects of leaving ones home and trying to
settle in a new place.
What is greater fame? That your contemporaries know how great you are?
Or that hundreds or thousands of years later, you are still remembered
for your greatness?
The coins being minted centuries later are a greater fulfillment of the
promise. (For that matter, saying Birkhas Avos and "Magein Avraham" at
least 3 times a day for 2-1/2 millennia and counting is yet greater.)
There does not seem to be much point in offering a band-aid many years
AFTER the Makka...
Who said this heals the makka? Rather, it shows that the tribulations
our ancestors went through had a purpose and came with a berakhah.