Necronomicon I is a Misc in Kingdom Come: Deliverance.
"A book of incantations to invoke demons written in a cryptic language."
Liber de Mortuis - NECRONOMICON INITIUM
ZI ANNA KANPA!
ZI KIA KANPA!
Necronomicon I can be acquired at the following locations
Found in the big monastery in Sasau. It's located on the 2nd floor library in a large cabinet, 2nd shelf from the top laying down on the left hand side. The key to the cabinet can be found in a chest in a few rooms over.