The Aryan language had both ‘bh’ and ‘b’ sounds as attested in early vedic literature. The Iranian branch of Aryan language lost the ‘bh’ sound some time around the beginning of the first Millennium BC as seen in the language of Avesta (1000BC) and the old Persian inscriptions of Iranian Achamenides Dynasty (559-330BC). Both these languages retained the ancient ‘b’ but avestan language, with which Pashto in connected, manifested change of ‘b’ to ‘v’ in certain positions. The same tendency is clearly seen in Pashto language where ancient ‘b’ is changed to semi vowel ‘w’. As against this the modern Persian which has descended from Old Persian has retained the ancient ‘b’ but has changed ‘w’ to ‘b’ in most positions. This article explains the above changes by giving examples from ancient languages and at the same time analyses some incorrect deductions drawn by some of our historians from words or names having the letter ‘b’ as word initial.