 However, Toland's notice would imply that the unnamed deceased former owner was a prominent anti-Trinitarian or Unitarian by religion; and Fremaux conjectures that the manuscript may have been brought to Amsterdam by Christopher Sandius (1644-1680), either from his own activity as a collector in Poland; or more likely from his acquisition of the papers of Giovanni Michele Bruto (1517-1592), who had assembled an extensive collection of manuscript sources in Hungary and Transylvania.Cramer had published an edition of Bruto's theological writings in 1698, and Fremaux speculates that Cramer might have come across the Gospel of Barnabas in the course of his researches within Sandius's library in Amsterdam.Otherwise, Slomp has proposed that Gregorio Leti (1630–1701), whose Amsterdam library had been auctioned-off following his death, could be the unnamed former owner of the Italian manuscript.