Retrograde in History · 1846
Mallarino–Bidlack Treaty
On December 12, 1846, Mercury was mid-loop — retrograde in Sagittarius, tracing backward through 18°58′ of the sign.
WhenDecember 12, 1846♐︎Sagittarius 18°58′Rx windowDec 2 – Dec 22, 1846
The record
On 12 December 1846 U.S. minister Benjamin Alden Bidlack and New Granada's commissioner Manuel María Mallarino signed the Mallarino–Bidlack Treaty.
Coincidence, not causation: the date is real and ephemeris-based, but a retrograde window is observed, never blamed. For entertainment, not navigation.