Crespin became famous, however, for his Book of Martyrs. In it he listed many who had been executed for heresy between 1415 and 1554.
Namun, Crespin menjadi termasyhur karena karyanya Book of Martyrs (Buku tentang Para Martir), yang memuat daftar orang - orang yang dieksekusi karena heresi antara 1415 dan 1554.