Additional recommended reading: https://en.m.wikipedia.org/wiki/History_of_Freemasonry
In a biography dealing with the leadership of Freemasonry, it is useful to look not only at the nature and purpose of that institution, but also at its history. Clearly, historical reflection is necessary in order to anchor and enhance the understanding of what a Grand Master is, what he does and where he comes from. A discourse on Masonic history, in the context of this book, must be brief, even though the subject itself is vast, as testified by the huge number of books and publications which have been dedicated to its study. That which follows here, therefore, can only be a Spartan and unelaborated attempt on the subject.
Freemasonry originated from the guilds of operative stonemasons (known as lodges) which flourished in Europe, and Britain in particular, during the Middle Ages. Stonemasonry was then a most important craft, the manifestation of which can still be seen today in the many cathedrals, churches, castles and manors which survive from those times.
However, operative lodges were somewhat different from the guilds associated with other medieval trades. Stonemasons were itinerant workers who were forced to travel to renew their employment as each building project was completed. The fluid nature of the operative craft, therefore, posed many problems in the determination and recognition of qualifications and skills. In the largely illiterate society that then prevailed, lodges acted as trade regulatory bodies, not only in the area of professional skills and the recognition of practical qualifications, but also in the moral and religious standards of their members. In response to these needs the operative craft, through its lodges, evolved a system of instruction that combined practical knowledge and morality. The medieval lodge system also, of necessity, involved a degree of privacy and secrecy, so that the supposed skills of a newly- arriving stranger could be readily checked. 
The march of technology in building saw the decline of stone construction in the late Middle Ages, and with it the steady demise of the stonemason's craft and the operative lodges. As a reaction to this decline, the passage of time saw increasing numbers of men who were not stonemasons being received into lodges. By the eighteenth century lodges had largely ceased to be composed of stonemasons. These non-operative members became known as 'speculative' or 'symbolic' Masons.'
The decline of operative Masonry and the rise of the 'speculative' kind also heralded the end of the itinerant nature of some lodges. All lodges could now find permanent homes in urban locations. The premier Grand Lodge of England was formed on 24 June 1717 by four London lodges. No records remain of the event. Our knowledge of this foundation meeting comes largely from Anderson's 1738 edition of the 'Constitutions' of the Grand Lodge. According to Anderson, representatives of the four lodges met in 1716 and determined upon a meeting in the following year to revive the Annual Assembly and Feast, at which they would 'chuse a Grand Master from among themselves till they should have the Honour of a Noble Brother at their Head'. 
The first meeting was duly held and one Anthony Sayer, Gentleman, was elected as the initial Grand Master. He thereupon 'commanded the Master and Wardens of Lodges to meet the Grand Officers every Quarter in Communication'. Nonetheless, for the first four years of its existence the Grand Lodge only met annually, with its only business being the election of its Grand Master and Grand Wardens.  There would seem little doubt, therefore, that the formation of the Grand Lodge was not prompted by a perceived need of central organisation, but simply to enable the London lodges to meet together socially -- bearing in mind that members were now largely of the 'speculative' kind. The only other discernible reason was a desire to elect a 'noble brother' as their leader with, one suspects, the view of raising the social status of their organisation. Success first occurred in 1721, with the election of John, 2nd Duke of Montagu, as Grand Master. Since then the Grand Lodge of England has continuously had either a Peer of the Realm or Prince of Royal Blood as Grand Master.
It was not until the 1720s that the Grand Lodge commenced its emergence as a regulatory body. In 1723 the first secretary to Grand Lodge was appointed, and regular minutes kept. Grand Lodge started to meet more frequently, and its Constitutions were published. The membership of nobles attracted press publicity, and the number of lodges rapidly expanded - not only in England, but overseas as well. An independent Grand Lodge was formed in Ireland in 1725, followed by a new counterpart in Scotland in 1736.
The early years of organised English Masonry, however, proved far from harmonious, and the eighteenth century saw six rival Grand Lodges emerging at various times to claim jurisdiction over England or part of it. Only two of these persisted with any substantial following. These were the Premier Grand Lodge of England (often referred to as the 'Moderns Grand Lodge', or 'Moderns'), and the Grand Lodge of England According to the Old Constitutions (known as the 'Atholl Grand Lodge', or 'Antients'). The Moderns according to their opponents, introduced unacceptable changes into the rituals and practices of Freemasonry. 
The Antients Grand Lodge, apparently spawned by their opposition to these 'innovations', had emerged by 1751. It was originally established by Irish Masons then living in England who were 'unhappy' with the Premier Grand Lodge. Both these Grand Lodges developed and expanded their lodges and membership over succeeding years. This occurred quite independently of each other. Both Grand Lodges were rivals, often bitter rivals, and each considered the other to be irregular. Generally, the Moderns tended to attract more 'upper class' members, while the Antients had a broader membership base. The two Grand Lodges developed quite a number of divergent practices.However, except at official level, ordinary Masons were not particularly interested in this rivalry, and most members on both sides either ignored these divergences or paid little heed to them.
As Freemasonry spread rapidly around the world, the passage of time saw the old discords largely disappear. Newer members on both sides had no understanding of the issues involved, and even less interest in them. The pressure for union increased, and the chance of such an occurrence was greatly enhanced on the election of HRH the Duke of Sussex as Grand Master of the Moderns, and his brother HRH the Duke of Kent as Grand Master of the Antients. Joint committees of the two Grand Lodges met and overcame remaining problems, and the union was happily effected on 13 May 1813. The title United Grand Lodge of England was adopted, and the Duke of Sussex became its first Grand Master. 
The United Grand Lodge of England subsequently developed into the largest Masonic body in the world, having lodges chartered on every continent. English Freemasonry has directly or indirectly been the source of all Grand Lodges elsewhere on the globe. The Grand Lodges of Ireland and Scotland, respectively the second and third Grand Lodges formed, have also chartered lodges all over the world. As Masonry grew in strength in various localities, other Grand Lodges were formed.
Most Western European countries possess a Grand Lodge, as do virtually all the provinces of Canada, and the States of America. Similarly, most South and Central American countries have at least one Grand Lodge each. Diverse countries such as Israel, South Africa, India, Japan and the Philippines are likewise blessed. In Australia, each of the six states has long possessed a Grand Lodge, with the first being formed in South Australia in 1884.
It needs to be appreciated that Freemasonry is not one worldwide confederation. There are more than a hundred independent Masonic Grand Lodges in the world, most of which maintain 'fraternal relations' with each other - diplomatic relations,to put it in non-Masonic terms. Originally, relations between Grand Lodges were handled by what are known as'Grand Representatives'. These were senior Grand Lodge officers who acted as something akin to ambassadors. This system has long fallen into practical disuse, with business between Grand lodges being handled by their respective Grand Secretaries. Nonetheless, most Grand Lodges still appoint Grand Representatives, who act on an honorary basis.
There are also quite a number of differences in the constitutional, operational and ritualistic practices between Grand Lodges. They are only limited by a set of basic notions known as 'The Ancient Landmarks of the Order'. Even so, there is far from universal agreement as to what these are, or their number. Noted Masonic author Harry Carr defines a landmark as a principle or tenet that has 'always existed' in Masonic practice, and as an element in the form of the Society of such importance that, if removed, Freemasonry would no longer be Freemasonry.
1 Pick, F.L. & Knight, G.N., The Freemasons' Pocket Reference Book, 3rd Edition (Frederick Muller, London, 1983), p.37; pp.224 et seq.
2 Hamill, John, The Craft (Aquarian Press, England, 1985), p.41.
3 Op. cit., p.42.
4 Henderson, K.W., Masonic World Guide (A. Lewis, London, 1985), p.129.
6 Op. cit., p.26