Armor cuirass, Ottoman Empire (Turkiye), 16th century AD
Medieval (500 AD - 1600 AD)
(media.piefed.social)
Probably not by Janissaries. Janissaries were generally archers (early period) or musketeers (most of their existence), and heavy armor is more a burden than a help for those disciplines.
Very likely an option for Sipahis, though, who were noted to fight in heavy armor!