What is the reality of Allopanishad?

 

What is the reality of Allopanishad? Who wrote it ? How new Upanishads are created?

 The Upanishads are many, and said to be one hundred and eight, but some declare them to be still larger in number. Some of them are evidently of a much later date, as for instance, the Allopanishad in which Allah is praised and Mohammed is called the Rajasulla. I have been told that this was written during the reign of Akbar to bring the Hindus and Mohammedans together, and sometimes they got hold of some word, as Allah, or Illa in the Samhitâs, and made an Upanishad on it. So in this Allopanishad, Mohammed is the Rajasulla, whatever that may mean. There are other sectarian Upanishads of the same species, which you find to be entirely modern, and it has been so easy to write them, seeing that this language of the Samhitâ portion of the Vedas is so archaic that there is no grammar to it. Years ago I had an idea of studying the grammar of the Vedas, and I began with all earnestness to study Panini and the Mahâbhâshya, but to my surprise I found that the best part of the Vedic grammar consists only of exceptions to rules. A rule is made, and after that comes a statement to the effect, “This rule will be an exception”. So you see what an amount of liberty there is for anybody to write anything, the only safeguard being the dictionary of Yâska. Still, in this you will find, for the must part, but a large number of synonyms. Given all that, how easy it is to write any number of Upanishads you please. Just have a little knowledge of Sanskrit, enough to make words look like the old archaic words, and you have no fear of grammar. Then you bring in Rajasulla or any other Sulla you like. In that way many Upanishads have been manufactured, and I am told that that is being done even now. In some parts of India, I am perfectly certain, they are trying to manufacture such Upanishads among the different sects. But among the Upanishads are those, which, on the face of them, bear the evidence of genuineness, and these have been taken up by the great commentators and commented upon, especially by Shankara, followed by Ramanuja and all the rest.

 - Swami Vivekananda (Complete Works of Swami Vivekananda - Lecture given at Madras)