[1] Supported by Dafina Doamna and some of the boyars, he came to the throne in Iaşi after Dabija's death, but was soon ousted after his opponents appealed to the Ottomans, unjustly claiming Duca's rule was corrupt.

The policy of increased taxation led to the uprising of Mihalcea Hâncu in October 1671, crushed the next year after Ducas received Ottoman help.

But, as Ducas failed to provide supplies needed for the War against the Polish–Lithuanian Commonwealth, with the Sultan Mehmed IV's life placed in peril at the attack of Kamianets-Podilskyi, the Ottomans swiftly replaced him with Ștefan Petriceicu.

His overlord appointed him as hetman over the newly gained regions, in 1680 or 1681, after much bribery strained the Moldavian treasury as much as the request that Ducas had placed on the taxed categories that they contribute to his daughter's dowry.

Helped by his absence and aware of the complete failure of the Ottoman plans, boyars throughout the land rebelled, following Ștefan Petriceicu's command, and welcomed the invading Poles and Cossacks.