To many in the West, he remains the religious leader who was weighed against precious stones, the race horse owner who won five Derbies or the man whose eldest son, Aly Khan, once married Rita Hayworth.
For those who are more familiar with the East, he was the most gifted hereditary religious leader or forty eighth Imam of some 12 million Ismaili Shia Muslims who are to be found from the Great Wall of China to the southern tip of Africa, a direct descendant of Prophet Muhammad and a true believer in the percepts of Islam.
Students of history or the older generations may recall The Aga Khan as a statesman, who was received by Queen Victoria in 1898, became the youngest member of Lord Curzon's Indian Legislative Council in 1902, presided the Muslim League from 1906 until 1912 and led the Muslim deputation to the Round Table Conference in 1930 which paved the way for the independence of the sub-continent.
In addition, 1937 saw him preside over the ill-fated League of Nations when he later visited Hitler in Berchtesgaden in a last-ditch effort to avert war.
For me, of course, he was all of these things and many more. It remains challenging but essential for the son of any great father to do away with the labels which are inevitably attached by history to the public figures of our time and to attempt an impartial assessment. This I hope to do in a book some day.
My father was, first and foremost, a deeply religious man who had no difficulty in integrating an active political and social life and everything it entailed in terms of formality and obligations in the post-Victorian era, with the close communion with God which is the aspiration of every practising Muslim.
The older staff at the Ritz in London or the Swiss strolling in front of the Hotel de Russie in Geneva in the thirties, might recall the Aga Khan facing Mecca at prayer time on one of the balconies, completely oblivious to the stares of surprised bystanders. Muslims who journey westward are no longer the exotic objects of interest which they were in those days.
It was this Islamic sense of unity in all forms of life which confirmed my father's faith in a God-governed order. He achieved a synthesis which enabled him to conciliate his faith in the Almighty as well as in Darwin's theory of the origin of the species which swept across Europe in his youth and generated such heated debate.
It was difficult for him to separate what he called protoreligion and protoscience: they made their journey like two streams, sometimes mingling, sometimes separating but running side by side. For him Marxism was a religion where matter is the supreme power.
He sought the company of scientists since the time when, against orthodox medical opinion, he had himself inoculated publicly at the age of 20 during the Bombay epidemic of bubonic plague in 1897. This prompted others to follow and many lives were saved as a result.
I have not forgotten his heated conversations with Professor Leakey in Nairobi when the first discoveries of the earliest remains of man were made in the Rift Valley, or his exchanges with Professors Bogomoletz or Niehans on longevity.
My father was a pragmatist when it came to politics. His main concern was the welfare and development of his community and as such, he deliberately chose to work closely with the administering power in the countries where the Ismailis lived. In 1914 and again in 1939, he resolutely threw in his lot with the British and spared no effort to ensure that Muslims everywhere should fight alongside the allies.
This nearly cost him his life in 1917 when the German Secret Service sought to assassinate him in Lucerne. This left him unshaken and he never chose to have any form of personal protection.
His optimistic faith in man and his desire to avert war had caused him to be swayed in the early Thirties by those of his friends - including the Clivden set - who advocated appeasement in the face of the mounting Nazi threat.
He thus mistakenly chose to support the Munich settlement and said so in a much criticised article in The Times. It was with a sense of bitter disappointment, therefore, that he vigorously denounced Hitler's aggression and at once issued a strong manifesto urging his followers to give their fullest support to Britain. This was the aim of his visit to India in 1939-40 when he persistently campaigned in favour of British war aims and endeavoured to act as an intermediary with Reza Shah of Persia.
His foresight in other spheres of political analysis was positively uncanny, however; long before the word "Commonwealth" came into use, my father advocated, at the beginning of the century, the creation, under British inspiration and guidance, of a South Asian federation of self-governing states extending from Malaysian peninsula to the confines of Egypt.
When the first world war ended, he endorsed the building up of a Federal Union of Arab States and Turkey with a single defence force and a united foreign policy. This could have achieved practical results in the security and stability of the Middle East far transcending, in my father's words, "anything that makeshift, haphazard policies of the years since the end of the conflict and particularly piecemeal withdrawal of political suzerainty by Britain have been able to effect".
While working for independence, he was concerned about the post-colonial vacuum and big-power rivalry in the Muslim world following the breakup of political entities through nationalism and violent change.
My father abhorred injustice and fought actively for both human and civil rights at a time when it was hardly a fashionable pursuit. He resigned from the exclusive St. Cloud golf club near Paris when some members objected to Sugar Ray Robinson - the black boxer - playing on the links.
In Aix-Les-Bains, one day, he rebuffed the pompous head waiter of the hotel Splendide who refused to seat a large group of Senegalese students and promptly invited them to a three star lunch.
He was deeply shocked by the ruthless and arrogant discrimination practised by whites in America, India and China. During his visit to China in 1906, he remarked: "Within the foreign settlements the general attitude towards the Chinese was little short of outrageous. All the better hotels refused them entry. From European clubs they were totally excluded. We hear a great deal about the colour bar in South Africa today. In China, in the early years of this century, the colour bar was rigidly imposed - not least offensively in discrimination against officials of the very government whose guests, under international law, all foreigners, were supposed to be. Is it any wonder that the Chinese intelligentsia long retained bitter memories of this attitude?".
Absolute power, if unenlightened, was equally despised: my father's comments on the Qajar Shah Musafaraddin - to whom he was closely related - are indicative in this respect: "He exhibited, in an especially lurid light, all the dangers of old-fashioned autocratic oriental monarchy. However incompetent, silly, or criminal such a despot was, not one of the able and intelligent statesmen of the world around him ever stood up to him and told him the truth about himself. The mysterious prestige surrounding kingship and the blood of kings induced a kind of mental paralysis even in good and sincere men, so that they were quite unable - in the interests of their king and their country, even in their own interests - to give true advice and guidance."
For my father, education was understandably a priority and his community exemplifies the success of his policies. Ismaili men and women, the latter amongst the first to shed the veil, are well equipped in this respect. Ismaili institutions have provided a net work of social, economic and cultural amenities which are unrivalled in many developing countries. These were made possible to a great extent by the wise administration of funds raised in connection with the traditional jubilee weighing ceremonies.
The community took up the lion's share of my father's time and attention. This was - as he put it - his job. Thousands of Ismailis were received every year and those who did not meet their Imam individually, were in contact with him when he visited their countries. He was highly accessible and seldom left a letter unanswered.
And yet he found time for journeys to centres of arts and culture and I recall the importance he attached to my visiting the great museums of Europe. He owned no collections of his own, cared little about the decor of his residences and spent a great deal of time in hotels - but loved the opera and the ballet. Serge Lifar, the great Russian dancer, will never forget the time when my father gave him a considerable contribution in cash - wrapped in newspaper - to get his company out of financial doldrums
If greatness there was, during his long and active life, then it rested on an oddly balanced mixture of Islamic faith and philosophy and Western logic and science born out of the industrial revolution; it allowed for reform and vision in both thought and action and, in retrospect, would seem to disclaim Kipling's famous pronouncement, as my father was truly the product of a meeting between East and West.
A centenary is a time to pause, look back establish a link between the prologue of the past and the realities of today.
My father undoubtedly left a deep and meaningful imprint on the Ismaili community and the Muslim world. In addition, he contributed in no small way to shape the course of recent history.
But for me, his message remains that of a tolerant and loving father, always at peace with himself, particularly in sickness and when life ebbed away, convinced, in his own words, that he "experienced moments of enlightenment and of knowledge of a kind which we cannot communicate because it is something given and not something acquired".
Courtesy The Times, 5th November, 1977. Copyright: Times Newspapers Ltd.1977.