History
On Preserving Health (Liber de conservanda sanitate) – John XXI
John XXI
A medieval medical treatise by John XXI on preventive health, blending Galenic humor theory with practical advice for…
Design
Syncategoreumata – John XXI
John XXI
John XXI's Latin treatise on syncategorematic words explores how particles like 'is' and 'begins' shape meaning and truth…
Literature
Summulae logicales – John XXI
John XXI
Summulae logicales is a Latin school manual of logic attributed to Peter of Spain, identified with Pope John…
Biography
On the Eye (Liber de oculo) – John XXI
John XXI
The Liber de oculo is a medieval Latin ophthalmological treatise attributed to Petrus Hispanus, also known as Peter…
Christianity
The Treasury of the Poor (Thesaurus pauperum) – John XXI
John XXI
The Treasury of the Poor is a Latin medical recipe collection attributed to Peter of Spain, offering practical…