Professor Mark Hill QC is an adjunct professor at Cardiff University, Pretoria University, Notre Dame University Law School, Sydney and King’s College, London; and is a fellow at the Center for the Study of Law and Religion at Emory University, Atlanta. He practices at the Bar in London and sits as a judge on the Midland Circuit.
The vast majority of scholars of law and religion tend to focus on the interface between church and state. This is unsurprising. From the medieval philosophers to the present day, the respective spheres of the spiritual and the secular authorities have been the subject of contest and engagement. These are matters upon which I have written and lectured over the past thirty years. But I have long been intrigued by the internal laws of religious organizations, which led me to write my definitive textbook Ecclesiastical Law on the law of the Church of England, now in its fourth edition. The Church of England is unusual, being established by law as a state church. Its laws (Measures) have the same status as Acts of Parliament .
It struck me that however encyclopedic one’s knowledge of the laws of a Christian denomination might be, the discrete discipline of comparative church law hardly existed at all. Each church had its own experts, but their parameters of knowledge—like mine—were constrained to the law of their particular tradition. So in 1999, along with long-term collaborator and friend, Professor Norman Doe, we established a Colloquium of Anglican and Roman Catholic Canon Lawyers, with the modest ambition of hosting symposia comparing the canon law of the Anglican Communion with that of the Latin Catholic Church. This was a rich and rewarding project, summarized in a ten year review, which is still continuing with a fresh generation of canon lawyers and periodic publications.
With the success of this bilateral initiative, Professor Doe and I decided to be more ambitions and to look at the internal laws of a wider range of Christian denominations. Fired up by our common interest in the project, Doe did the heavy lifting with his treatise, Christian Law: Contemporary Principles (Cambridge University Press, 2013), but I was reluctant to let this work ossify as an academic text. I wanted to road test these principles to see if they were recognized across all Christian denominations, and to explore whether their study might prove of value in the ecumenical endeavor.
So I assembled an ecumenical panel of lawyers, theologians and church leaders from across the Christian tradition, who met in Rome on several occasions between 2013 and 2016, to stress-test Does assertions and to draft a Statement of Principles of Christian Law. The panel identified principles of church law common to the Catholic, Orthodox, Anglican, Lutheran, Methodist, Reformed, Presbyterian and Baptist traditions whose existence can be factually established by observation and comparison. The shared principles are illustrative of visible unity between the various churches.
The panel continued to meet and in 2015 responded to the World Council of Churches’ consultation document The Church: Towards a Common Vision (2013) from an overtly juridical perspective. The Panel met with the WCC’s Faith and Order Commission in Geneva. The Commission Director recognized that law could be considered a potential unifying force in global ecumenism, being an element of the true church. Hitherto the focus had been on doctrine and tradition.
Church Laws and Ecumenism  is the first book to have been written on these significant developments in comparative church law and ecumenism. As the Preface states:
It provides not only the fruits of an understanding of church laws within ten Christian traditions, but critically evaluates the Statement of Principles against the laws of these individual ecclesial communities.
The volume provides an opportunity to re-imagine ecumenism as—in part at least—a profoundly legal matter in which church law may be used as a creative force for Christian unity. It enables the ecumenical movement to recognize the deeply shared experience of Christians in their use of regulatory instruments, their fundamental relationship with theology as applications of it, and their place in the wider context of the demands of civil law. Today there is a growing appetite to re-invigorate ecumenism—particularly under the auspices of receptive ecumenism—for separated churches to reflect in scholarly and practical ways on what Christians might learn from one another, in the realm of action, and come to appreciate more fully how church law may help (or hinder) the movement towards greater visible Christian unity.
Access to a statement of Christian laws enables government to understand what opportunities and constraints the rules of a church place on its dealings with the state and society. State courts often deal with Christian obligations in religious freedom cases, the state legislates on matters which concern Christians, and in, for example, the field of charity law, state administrative bodies need to understand the juridical standards of accountability prevailing within the churches. The COVID-19 emergency has highlighted the need for governments to be literate in the way in which churches structure and regulate themselves.
In terms of methodology, each of the contributors to this volume was encouraged to think freely about the sources and forms of church law in their tradition. For some, the term “law” was problematic; and “polity” or “order” was preferred. On whom is the law binding? What are the theological or doctrinal foundations of the law? Each chapter considers what principles prove to be unproblematic and problematic from the perspective of the different traditions studied. How can the principles be reconciled to the norms of each denomination? Each chapter offers an evaluation of the Statement of Principles in terms of: the extent to which the principles reflect the doctrinal or theological position of the tradition; and the value of the Statement for the tradition and how it might be developed further. The conclusion offers a general assessment of how the Statement of Principles of Christian Lawhas been received thus far by Christian leaders and its wider significance for the global ecumenical movement. The volume is a modern take on the work on the medieval glossators in universities such as Bologna. Instead of commentating on the canons of the Catholic Church, they provide a practical analysis of the Statement of Principles of Christian Law, rooted in reality and informed by the expertise and experience of the authors.
It was uplifting for this project to receive the imprimatur of His Holiness Pope Francis last year. In a speech to mark the fiftieth anniversary of Conference of the Society for the Law of the Eastern Churches, he stated that “Canon law is essential for ecumenical dialogue,” and continued:
Many of the theological dialogues pursued by the Catholic Church, especially with the Orthodox Church and the Oriental Churches, are of an ecclesiological nature. They have a canonical dimension too, since ecclesiology finds expression in the institutions and the law of the Churches. It is clear, therefore, that canon law is not only an aid to ecumenical dialogue, but also an essential dimension. Then too it is clear that ecumenical dialogue also enriches canon law.
Much the same has been said by His All-Holiness Bartholomew, the Ecumenical Patriarch of Constantinople, in his opening address to the conference. He welcomed the Statement of Principles of Christian Law and described it ‘as designed to fill the historical juridical deficit in the ecumenical enterprise’.
Comparative church law is now firmly in the sights of canonists and ecumenists and is recognized in the academy as a fresh and vibrant discipline in its own right. Norman’s Doe’s edited volume, Church Laws and Ecumenism is an invaluable aid to navigation. It is a rich resource for dialogue and reflection and deserves to be widely studied.
 See Hill, Ecclesiastical Law (OUP, 2018), chapter 2.
 See Mark Hill, “A Decade of Ecumenical Dialogue on Canon Law: Report on the Proceedings of the Colloquium of Anglican and Roman Catholic Canon Lawyers 1999–2009,” 11 Ecclesiastical Law Journal (2009): 284-238.
 Catholic (Roman and Eastern), Orthodox, Anglican, Lutheran, Methodist, Reformed, Presbyterian, Baptist, Pentecostal, and the United Churches.
 Church Laws and Ecumenism: A New Path for Christian Unitywas published this year byRoutledge. It is edited by Norman Doe, Director of the Centre for Law and Religion at Cardiff University. Chapter 5, on The Anglican Canonical Tradition was contributed by Mark Hill QC.