Ivo of Chartres (d. 1115) was a central figure in the secular and ecclesiastical affairs of his time, and his wide-ranging works mark an important stage in the development of canon law as a separate discipline. The numerous cases he decided as a judge or commented upon in his extensive correspondence, the canon-law collection he compiled, and the elaborate preface he wrote as an introduction to this collection provide detailed insight into how Ivo understood canonical tradition on diverse questions ranging from the Eucharist to royal marriages, from penitential theology to procedural law. An issue he returned to frequently was how ecclesiastical law in many cases was so diverse that it ultimately was left to the discretion of the judge which traditions to follow and how to interpret the law. Just as canonical tradition often included precedent both for harsh judgment and more lenient attitude, the judge had to decide in every single case whether to apply the rigor of the law or to soften it. The right choice, Ivo taught, would depend on the individual circumstances of the case but should always be guided by the spirit of charity.