In several of the autocephalous Eastern Orthodox churches and Eastern Catholic Churches, the patriarch or head bishop is elected by a group of bishops called the Holy Synod. For instance, the Holy Synod is a ruling body of the Georgian Orthodox and Apostolic Church.
In Oriental Orthodoxy the Holy Synod is the highest authority in the church and it formulates the rules and regulations regarding matters of church's organisation, faith, service's order. .
But all these synods met only on certain occasions, for a short time, to discuss some one, or at most a few, of the burning questions. We shall find the predecessors of present Orthodox Holy Synods rather in permanent councils at the courts of certain chief bishops. Such councils formed themselves naturally, without any detriment to the monarchical principle. The bishop was always autocrat in his own diocese, the patriarch in his patriarchate. Nevertheless, when he had a number of wise and learned persons, clergy of his city, suffragan and titular bishops in his palace or near at hand, it was very natural that he should consult them continually, hear their advice, and then follow it or not as he thought best.
Two examples of such advisory committees established permanently under their bishops are famous. The Pope had at hand his suburban bishops, the Roman parish priests, and regionary deacons. Without going through the formality of summoning a diocesan or provincial synod he could always profit by their collected wisdom. He did so continually. From the fact that it was normally just these three bodies who joined to elect a new pope when the see was vacant they had additional importance, and their views gained additional weight. The assembly of these persons around the pope as a permanent institution was the Concilium apostolicœ sedis to which papal letters from the fifth to the eighth or ninth centuries often refer. The same name was, however, also used for specially summoned Roman provincial synods, which were quite a different thing. The Concilium apostolicœ sedis in the first sense evolved into the College of Cardinals, who still form a kind of permanent synod for the pope to consult. But there has never been any idea of so radical a revolution as the government of the Roman Church by a synod. Once the pope was lawfully elected he was absolutely master. He could consult his cardinals if he thought fit, but after they had given their opinions he was still entirely free to do as he chose.
A nearer example for the Orthodox was a similar institution at Constantinople. As the œcumenical patriarchs gradually grew in importance, as they spread the boundaries of their jurisdiction and were able more and more plainly to assert a kind of authority over all Eastern Christendom, so was their palace filled with a growing crowd of suffragans, auxiliary and titular bishops, chorepiscopi, and archimandrites. Bishops from outlying provinces always had business at the patriarchal city. The presence of the imperial court naturally helped to attract ecclesiastical persons, as well as others, to Constantinople. The Arab and Turkish conquests in Egypt, Syria, and Asia Minor added further to the number of idle bishops at court. Refugees, having now nothing to do in their own sees, kept their title and rank, but came to swell the dependence of the œcumenical patriarch.
So from the fifth century there was always a number of suffragans and titular bishops who established themselves permanently at Constantinople. Again, it was natural that these people should justify their presence and spend their time by helping the patriarch to administer his vast province and by forming a consulting synod always at hand to advise him. So at Constantinople, as at Rome, there was a kind of permanent synod, at first informal, then gradually recognized in principle. This was the "present synod", "synod of inhabitants" (synodos endemousa), that became for many centuries an important element in the government of the Orthodox Church.
The council then proceeded with the business in hand without expressing either approval or dislike of the permanent synod at Constantinople. Such was very much the attitude of the Church generally as long as the Endemusa Synod lasted. It in no way affected the legal position of the Patriarch of Constantinople, nor was it in any sense a government of his patriarchate by synod. In this case too, as at Rome, the consulting synod had no rights. The patriarch governed his subjects as autocrat, had the same responsibilities as other patriarchs. If he chose to discuss matters beforehand with "the most holy bishops who dwell in the mighty city" that proceeding concerned no one else.
So the Endemusa Synod continued to meet regularly and became eventually a recognized body. So little did the patriarchs fear a lessening of their authority from it that it was to them rather an additional weapon of aggrandizement. There was a certain splendour about it. The œcumenical patriarch could contemplate the college of cardinals marshalled around the Western throne with greater complacency when he remembered his hagiotatoi endemountes episkopoi. Much more important was the fact that his orders and wishes could be constantly announced to so many obedient retainers. And bishops from outlying parts of the patriarchate who spent a short time at Constantinople, approached their chief through the synod; they too were invited or commanded to attend its sessions as long as they were in the city. So they heard the patriarch's addresses, received his commands, and carried back to their distant homes a great reverence for the lord of so many retainers. The Endemusa Synod was abolished only in quite recent times as part of the general reorganization of the patriarch's ecclesiastical and civil jurisdiction since the hatti-humayun of 1856.
This permanent synod then may be considered as a kind of predecessor of the modern Orthodox Holy Synods. It had accustomed people to the idea of such assemblies of bishops and made the acceptance of the new synods among so conservative a folk as the Orthodox possible. But the present Holy Synods are in no sense continuations of the Endemusa. In spite of a general likeness there is this fundamental difference between the old synods and the new ones: the Endemusa had no sort of jurisdiction; it was simply a consulting body, itself entirely subject to the monarchical patriarch. The modern Holy Synods, on the other hand, are the supreme lawgiving authorities over their Churches; they have absolute authority over every metropolitan and bishop. Laws in Churches that have such synods are made, not by the will of an autocrat, but by a majority of votes in synod. It is in short — what the older Church never dreamed of — government by Parliament.
A law in 1852 regulated its rights and duties. It met at Athens under the presidency of the Metropolitan of Athens. Four other bishops are appointed by the Government as members for a year by vote. The members took an oath of fidelity to the king and government. Their deliberations were controlled by a royal commissioner, who was a layman chosen by government, just as the Russian oberprocuror. No act was valid without the commissioner's assent. There were also secretaries, writers, and a servant all appointed by the State. The Holy Synod was the highest authority in the Greek Church and had the same rights and duties as its Russian model, and was is named in the liturgy instead of a patriarch.
After the proclamation of the Greek Republic in 1924, royal control of the Holy Synod naturally ceased, and with the elevation of the Metropolitan of Athens to an Archbishophric in 1932, the Archbishop began to be named in liturgies. Today, supreme authority is vested in the synod of all the diocesan bishops, who all have metropolitical status (the Hierarchy of the Church of Greece) under the presidency of the Archbishop of Athens and all Greece. This synod deals with general church questions. The Standing Synod is under the same presidency, and consists of the Primate and 12 bishops, each serving for one term on a rotating basis and deals with details of administration.
The Synod is chaired by the Patriarch of Alexandria and the members are the Church's Metropolitans, Bishops, Chorbishops and the Patriarchal Vicar for Alexandria.