Antiquarian and numismatist who became Hofrat (privy counsellor) and Director of the Ducal Library and keeper of the Cabinet of Medals in Gotha.
A student at the University of Helmstedt, he was appointed Professor of Greek and Oriental Philology there in 1736.1
On October 18, 1764, while visiting Gotha on his Grand Tour, Boswell went to see the Duke's Cabinet of Medals. He wrote that "[t]he Gentleman who has care of the Cabinet, was very intelligent" presumably referring to Schläger. He further wrote that Schläger "told me that he could discover counterfeit antiques because the veritable antiques were round in the edges as anciently they coined in a different manner from what they do now."
Schläger wrote a number of tracts and essays, mostly in latin and concerning the history of coins and medals, including "Index scriptorum editorum et edendorum" (1742), "Commentatio de numo Alexandri M." (1736), "Numophylacii Burkhardiani Pars I." (1740), "Historiae litis de medicorum apud veteres Romanos degentium conditione" (1741), "Dissertatio de debitore obaerato secundum jus Hebraicum et Atticum creditori in servitutem adjudicando" (1741); "Commentatio de numo Hadriani plumbeo et gemma Isiaca" (1742); "Dissertationum rariorum de antiquitatibus sacris et profanis fasciculus" (1742) and "Fasciculus novus" (1744).