Each country appointed assayers--usually a pair--whose responsibility it was to assure the purity of the coin metal and the accuracy of the coins' weight. The assayers' initials appear on the coins near the mintmark.
While the minting date doesn't always appear on cobs, it is on all the later types. However, since the obsolete note coin vignettes use the reverse, or non-date, side of the coin, the date is invisible. The range of possible dates for the coins in the vignettes can be determined from the mintmark/assayer combination, since it is usually known when the assayers were active.
For the bust coinage, mintmarks, the associated country, assayers' marks,
and the date range for coins bearing these marks are shown in the following
table:
Country/Assayer | 8 reales | 4 reales | 2 reales | 1 real | 1/2 real |
Mexico | |||||
FM | 1772-1778
1783-1801 |
1772-1777
1784-1801 1803 |
1772-1777
1784-1801 |
1772-1777
1785-1802 |
1772-1777
1783-1800 |
FF | 1777-1784 | 1778-1784 | 1778-1784
1786 |
1778-1785
1787-1788 |
1777-1784 |
FT | 1801-1803 | 1801-1803 | 1801-1803 | 1801-1803 | 1801-1803 |
TH | 1803-1810 | 1804-1808
1810 |
1804-1813 | 1804-1810 | 1803-1810
1813 |
HJ | 1809-1813 | 1809-1812 | 1810-1813 | 1810-1815 | 1810-1813 |
JJ | 1812-1821 | 1816-1821 | 1812-1821 | 1812-1821 | 1813-1821 |
Peru (Lima mint) | |||||
JM | 1772-1774
1824 |
1772-1773 | 1772-1773 | 1772-1773
1782 |
1772-1773 |
MJ | 1773-1780 | 1773-1780 | 1774-1780 | 1773-1780 | 1773-1780 |
MI | 1780-1787 | 1780-1787 | 1780-1788 | 1780-1787 | 1780-1787 |
IJ | 1787-1803 | 1787-1803 | 1787-1804 | 1787-1804 | 1787-1803
1805 |
JP | 1803-1824 | 1804-1821 | 1803-1823 | 1803-1823 | 1803-1821 |
Bolivia | |||||
JR | 1774-1776 | 1773-1776 | 1773-1776 | 1773-1776 | 1772-1776 |
PR | 1776-1795 | 1776-1795 | 1776-1795 | 1776-1795 | 1776-1795 |
PP | 1795-1802 | 1795-1802 | 1795-1802 | 1795-1803 | 1795-1802 |
PJ | 1803-1824 | 1803-1825 | 1803-1825 | 1803-1824 | 1803-1824 |
JP | 1823 | ||||
JL | 1825 | 1825 | 1825 | 1825 | 1823, 1825 |
J | 1824-1825 | 1825 | 1825 | ||
Guatemala | |||||
P | 1772-1784 | 1772-1783 | 1772-1783 | 1772-1783 | 1772-1783 |
M | 1785-1821 | 1785-1821 | 1785-1821 | 1785-1821 | 1785-1821 |
To
the Spanish Coins on American Notes home page