When it comes to Byzantine canon law, three names come to mind: Ioannes Zonaras, Alexios Aristenos, and Theodoros Balsamon, all of whom lived in the twelfth century. Aristenos was born presumably before 1100 and his death must have occurred after the year 1166 because we know that he attended a synod in Constantinople in that year. He had held important ecclesiastical and secular offices. In 1130, after an order of the emperor Ioannes II Komnenos (1118-1143), Aristenos made a commentary on the canons based on the Synopsis canonum, which was a summary of the canons, as its title implies. Aristenos wrote scholia on the canons of the Apostles, the Ecumenical Councils, local synods, and the canons of St. Basil the Great. Despite the fact that Zonaras was older than Aristenos, it was the latter who first wrote a commentary on the canons, which means that Aristenos’ commentary is the earliest of the three Byzantine canonists of the twelfth century. There is no doubt that Aristenos belongs to the most important personalities of Byzantine canon law, and admiration for his personality and work is expressed by contemporary writers, including Theodoros Prodromos, Georgios Tornikes, Nikephoros Basilakes, and the canonist Balsamon.
The present book offers a first critical edition of Aristenos’ commentary on the Synopsis canonum, an edition which is more than welcome given the importance of Aristenos and the fact that his commentary is the earliest of the three great Byzantine canonists. The edition of this book had a long history of obstacles, as the series editor Dieter Simon explains in detail in the preface. Spyros Troianos and Eleutheria Papagianni had been working for ten years (1990-2000) as summer guests at the Max-Planck Institute for European Legal History in Frankfurt on the collation of the manuscripts of this critical edition. Ludwig Burgmann assisted them significantly in the study and analysis of the preserved manuscripts and in selecting the actual manuscripts that were used for this edition. Papagianni and Troianos completed their critical edition in 2000. They handed their material over to Burgmann who would have looked critically into the material and would have put the final touch to this edition, including the writing of the Prolegomena to the book. As we read in the preface, Burgmann had also intended at some point to edit another version of the Synopsis (other than the one Aristenos had used) parallel to the Aristenos commentary. Burgmann had begun the collation of the existing manuscripts of this other (uncommented) Synopsis and had discussed this option with Simon and Troianos. Yet, due to Burgmann’s illness the whole project was delayed and unfortunately his death in 2019 put an abrupt end to this ambitious plan. Thus, although the core of the critical edition of Aristenos’ commentary was ready, the projected edition was abandoned until 2013. In that year Dieter Simon came to the rescue of a number of Byzantine projects that were active in the project ‘Edition und Bearbeitung byzantinischer Rechtsquellen’ of the Göttingen Academy of Sciences and Humanities. There were some problems that had to be solved at that point in order to complete this edition, as Simon describes in the book’s preface. In short, the present book was completed with the help of Kirill Maksimovič who also wrote the Prolegomena.
The book consists of a preface (pp. v-vi), Prolegomena (pp. ix-xli), bibliography (pp. xlii-xlvi), the abbreviations for the critical edition (p. xlvii), the critical edition itself (pp. 1-242) and extensive indices on sources (pp. 243-247), words (pp. 249-268) and names (pp. 269-272). In the Prolegomena, we read about Aristenos’ work and career; the older research on Aristenos’ canonical work; detailed information on the Synopsis canonum (its origin in the sixth century, transmission and revisions made in the following centuries, and editions); the contents of the Synopsis of Aristenos’ commentary, i.e. the order of the canons in this Synopsis (85 canons of the Apostles, 20 canons of first ecumenical council of Nicaea, 25 canons of council of Ancyra, etc.); detailed information on the transmission of the text; description of all preserved manuscripts and their relation to each other; former editions with explanatory and comparative information; the Slavic (old Serbian and old Russian) transmission of Aristenos’ commentary; and, finally, the principles used for this critical edition. Some information Aristenos’ references to secular law would have been welcome in the Prolegomena, along with a comparison of his style to that of Zonaras and Balsamon. Moreover, given also the prominence of Aristenos, one would expect a more elaborate biography of this renowned canonist. The section on his career in the book (“Zur Person des Aristenos”) consists practically of only one page, if one excludes the footnotes. We read here that Aristenos originated in the theme Hellas and that after he completed his legal education in his homeland, he moved to Constantinople after an invitation by the emperor Ioannes II Komnenos (1118-1143). According to Ioannis Polemis, however, Aristenos was a Constantinopolitan because, as Polemis notes, Nikephoros Basilakes (ca. 1115-died after 1182) mentions this in his encomium (panegyric) for Aristenos.
The index of words deserves extra attention and is extremely useful for the reader not only because it is extensive but also for the following reason. The Greek words in the index are accompanied by a German translation, which makes it easy for the reader to trace down a subject in which he or she is particularly interested. As stated in the preface, the elaborate index of Greek words with their German translations made essentially by Papagianni in co-operation with Troianos, after a suggestion of the project committee, replaces—up to a certain extent—the German translation of the text. It goes without saying that a German translation would have been better; however, this practical solution obviously helps the reader. The index of words refers the reader to the corresponding canon and line. I quote, for example the first word of the index: ἀβάπτιστος, ungetauft (= unbaptised): Chalc, 137. This word can be therefore found in the present edition, in the canons of Chalcedon, line 137. This system of references is very accurate since the actual line of the corresponding canon is given but perhaps the inclusion of the relevant page would have also been practical for the reader.
Undoubtedly the most important contribution of the book is the critical edition itself of Aristenos’ commentary of the Synopsis canonum. In reality, this is the first critical edition of Aristenos’ commentary. In previous editions (Beverigius, Oxford 1672 and Rhalles/Potles, Athens 1852-1859) the authentic text of the canons was mixed up with that of the Synopsis and the scholia of all three canonists, Aristenos, Zonaras, and Balsamon. Moreover, previous editors had used very few manuscripts. Beverigius had examined only four manuscripts for his edition and Rhalles / Potles based their edition on that of Beverigius, making only some additions. The present editors have consulted forty manuscripts of Aristenos’ commentary and have finally selected nine manuscripts for their edition. Maksimovič in the Prolegomena (pp. xxi-xxvi) distinguishes the selected manuscripts into three groups by counting corresponding readings in the critical apparatus. What is not so clear for the reader is how this arrangement of the manuscripts in groups (and consequently subgroups) is related to the actual assessment of the manuscripts used in the edition.
The field of Byzantine law has certainly made progress when it comes to critical editions of secular sources especially. In the field of Byzantine canon law, much remains to be done. This edition undoubtedly forms a sound step for the study of Byzantine canon law. Ideally a German translation of the Greek text and a commentary would have made this edition complete. However, given the obstacles that the edition of this book faced, as described in the preface, it is fortunate that the work was not lost and the critical edition of the text was completed after all. Scholars have quoted from Aristenos’ commentary mostly from the edition of Rhalles / Potles. We are lucky that prominent and experienced scholars have contributed to make the present critical edition and have brought to Byzantine scholarship a good, independent, and accessible edition of Aristenos’ commentary on the version of the Synopsis canonum he had used. The apparatus presents the readings of the nine manuscripts used and the divergences of the old editions. Whether the user will always be convinced by the choices made by the editors or not, he is now able to evaluate the alternatives.
 The Synopsis canonum upon which Aristenos made his commentary is a revision of the earlier Synopsis. On the history of the Synopsis canonum, its transmission and revisions, see the Prolegomena of this book, pp. XIII-XVIII. See also S. Troianos, Die Quellen des byzantinischen Rechts [übersetzt von D. Simon und S. Neye] (Berlin/Boston: de Gruyter 2017) pp. 146-47, and, in English, S. Troianos, “Byzantine Canon Law to 1100,” in W. Hartman and K. Pennington (eds.), The History of Byzantine and Eastern Canon Law to 1500 (Washington, D.C.: Catholic University of America Press, 2012) pp. 120-124.
 This other version had not been commented and Burgmann had intended to find out the relation between this Synopsis version and the one that Aristenos used.
 As far as the bibliography is concerned, the following title is missing from the bibliography: M. Krasnožen, “Kommentarij Alekseja Aristina na kanoničeskij Sinopsis” in Vizantijskij Vremennik 20 (1913), pp. 189-207.
 I. Polemis, Κείμενα για την Ελλάδα στην περίοδο των Κομνηνών. Ένας λόγος του Νικολάου Καταφλώρον και δύο ποιήματα του Ευθυμίου Τορνίκη, [Texts on Greece from the Period of the Comnenes -A Speech of Nicolaus Kataphloronand Two Poems by Euthymius Tornikes], in Greek, Athens 2020, p. 30.
 G. Beverigius (W. Beveridge), Synodikon sive Pandectae Canonum SS. Apostolorum et conciliorum ab Ecclesiagraeca receptorum…, vol. I-II, Oxonii (Oxford) 1672 and G. A. Rhalles / M. Potles, Σύνταγμα τῶν θείων καὶ ἱερῶν κανόνων… vol. I-VI, Athens 1852-1859.