Canon law: From synods to data protection

“Canon law connects centuries-old traditions with the legal and social challenges of today,” explains Professor Martin Rehak. Since October 2023, the Catholic theologian and legal scholar has been Chair Professor of Canon Law at LMU, with a special focus on administrative law and the history of ecclesiastical law. While Rehak’s main research interests concern the history of canon law, he also studies specific areas of current law. This includes the Church’s data protection regulations, which are governed at the regional or local level.

Martin Rehak studied theology and law at Julius-Maximilians-Universität (JMU) Würzburg. This was followed by a legal traineeship (Rechtsreferendariat), which took him to Munich, Eichstätt, Speyer, and Geneva. Subsequently, we worked as an attorney at a law office in Munich, where he mainly handled civil briefs. At the same time, he enrolled in the postgraduate Klaus Mörsdorf Program for the Study of Canon Law at LMU. Having obtained a licenciate degree in this program, he completed it with a PhD. In his doctoral thesis on the Munich scholar of canon law Heinrich Maria Gietl, Rehak combined biographical research with historical research into canon law.

For his subsequent postdoctoral thesis, which he also completed at LMU, Rehak elucidated Pope Benedict XVI’s decision to drop “Patriarch of the West” from his official titles. “This study ranges from the first centuries of the Church to the Second Vatican Council,” he explains. “I investigated how the governance of the Catholic Church was organized at the supra-episcopal level and what role the patriarchate played in the course of Church history – and still plays today.” From 2018 to his appointment at LMU, Rehak was a professor at JMU Würzburg.

Strong influence on civil marriage law

In his research and teaching at LMU, Martin Rehak addresses current topics in canon law as well as historical ones. “The development of canon law mirrors the transformation from a collection of individual decisions to a structured legal system,” says Rehak. Ecclesiastical law developed in the fourth century, for example, “when bishops met at synods and adopted canons – that is, ecclesiastical regulations.” These were later joined by papal decisions, which took the form of letters and adjudicated individual cases from all areas of Church life. “At the same time, secular laws – such as those of the Roman Emperor, or later the Frankish kings – played a role, as they touched on ecclesiastical topics and were enforced with state power.”

Over the centuries, these sources of ecclesiastical law were collected and passed on, until scholars in the 12th and 13th centuries began systematizing and annotating this vast body of canon law materials. “This period of scientific renewal, in which the first universities were established, saw the publication of several papal collections of canon laws, which were ultimately compiled in the Corpus Juris Canonici,” explains Rehak. “In the 19th century, the need grew for a streamlined and ‘modern’ codification. In 1917, the Codex Juris Canonici set out canon law in clear, abstractly formulated norms and forms the basis of today’s canon law.” Furthermore, canon law had a strong influence on civil marriage law until far into the 20th century.

Manuscripts from the Middle Ages

Alongside his academic work, Rehak engages in the practical business of evaluating ecclesiastical data protection issues. “The German Bishops’ Conference appointed me associate judge at the Interdiocesan Data Protection Court, which the Catholic Church established in 2018.” In his scholarly work, he reflects on cases he helps to judge: “There was a case, for example, where somebody working at a church institution applied for a job at another church institution and subsequently complained that the confidentiality of the process was not respected,” explains the expert in canon law. “And in another case, we had to determine whether the details of a person accused of sexual abuse were sufficiently anonymized in a diocesan study of abuse in the Church.”

Another topic that Rehak would like to address in the future is the edition of canonistic source texts. “Many texts from the crucial period for medieval canon law are available only in manuscript form.” Basic research on these sources is “very, very, time-intensive” and reliant on third-party funding. “Beginning with paleography, you have to develop an understanding for how bishops, monks, and canonists thought and argued back then,” says Rehak. “It’s a world of its own that you have to negotiate.”