Gold Tetarteron - Isaac I

Isaac I Komnenos seized the throne in a military coup against Michael VI in August 1057, marking the first time a general had successfully overthrown a Byzantine emperor through organized army revolt since the seventh century. His reign lasted barely two years before illness forced his abdication in favor of Constantine X Doukas — a decision he reportedly made against the counsel of his advisors, having entered a monastery to die. The tetarteron denomination itself was a reduced-weight gold issue introduced under Nikephoros II in the 960s, chronically controversial among merchants who distrusted its parity with the full nomisma.