Allopanishad

Allah Upanishad, or Allopanishad, is a book of uncertain origin written during Muslim rule in India during 15th to 16th century in the time of Mughal Emperor Akbar's reign.
Swami Dayananda Saraswati's book "Satyarth Prakash" (The Light of Truth) argues that the Allopanishad is not part of the Upanishad canon and it does not even appear in the Atharvaveda. The famous Muktikā canon, which was given by Rama to Hanuman as the list of authentic 108 Upanishads does not contain Allopanishad. Most scholars view that the book has been written during the Mughal era (possibly during Akbar's reign). Allopanishad describes Akbar as a messenger or prophet of God.
Views on authorship and authenticity.
In an issue of "The Theosophist", R. Ananthakrishna Sastri wrote that the work was written by "Pandits for monetary rewards" during the time of Muslim rule in India. He further remarked that the work was "not in the style of ordinary Upanishads" and its words "appear to sound more like Arabic". Bhattacharya and Sarkar categorize Allopanishad as an "Islamic Work" and write that it was written by a Hindu courtier of Akbar, as an "apocryphal chapter of the Atharvaveda". Charles Eliot suggested that the work may have been written in connection with the Din-i-Ilahi movement, and wrote that the work "can hardly be described as other than a forgery". Swami Vivekananda wrote that Allopanishad was evidently of a much later date and that he was told that it was written in the reign of Akbar to bring Hindus and Muslims together. Sadasivan writes that it was written by Brahmins for Akbar when he was experimenting with a new religion. Debendranath Tagore wrote in his autobiography that Allopanishad was composed in the days of Akbar with the objective of converting Hindus into Muslims. Bankim Chandra Chattopadhyay wrote that the Allopanishad was "the shameless production of some brahmin sycophant of Muslim rulers of India." Abraham Eraly states that the book was symbolic of the various cross-cultural pollination between Hindu and Muslim cultures during the time of the Mughals and was meant to bring the two communities together.