"Stephan Gerlach (Latin: Stephanus Gerlachius) was a German Lutheran theologian. Gerlach was an extremely important figure in the second half of the 16th century.
He was tasked with a special mission in Constantinople, namely to establish an alliance between Orthodoxy and Lutheranism against Catholicism. This mission failed, nevertheless, he signed the Brest Union.
From 1573 to 1578 he was in Constantinople as the first assistant and clergyman of the ambassador of the Holy Roman Empire - Baron David Ungnad von Sonnegg. He wrote a diary, one of the most cited sources in the historical literature about the situation in Constantinople in recent years of the "Kingdom of the Slavs", i.e. after the death of Selim II and just before the outbreak of the Long Turkish War." - (en.wikipedia.org 20.11.2021)
