Astrabel Zar was the original inventor of the Tomorrow Window.
As a young man exploring the haunted world of Gadrahadradon, Zar saw a vision of himself in the future being shot by a spectacled man. He then saw the Eighth Doctor and his companions, who gave him a set of notes so that he could invent the Tomorrow Window. He was also told to pass on his invention to Charlton Mackerel later in his life and was given other inventions as compensation for it.
Zar taught at a university where he passed on the notes of how to create the Tomorrow Windows to Charlton Mackerel. Zar then set out to use the other inventions he had gained to make himself a fortune.
Fifty years later Zar fulfilled the prophecy shown to him on Gadrahadradon and used himself as bait to Martin. (PROSE: The Tomorrow Windows)