I realized that other caterpillars produced beautiful butterflies or moths, and that silkworms did the same. This led me to collect all the caterpillars I could find in order to see how they changed''. In May 1665, Merian married Marrel's apprentice, Johann Andreas Graff from Nuremberg; _his_ father was a poet and director of the local high school, one of the leading schools in 17th-century Germany. <sep>, Pronoun: his <sep>, A: Marrel <sep>, B: Johann Andreas Graff