Medieval history was chronicled by assuming the myths and legends are true. Our country especially saw many significant changes in medieval times. These medieval chroniclers were essentially bards and poets who worked at the king's courts. And poetry cannot be called as a solid evidence because of the poetic exaggerations of author.
But we cannot reject these medieval chronicles as a plain legend because they are the only sources to know our past.
As for the modern chroniclers, we have carbon-dating mechanism, which with precision tells the age of the ruins. We have methods to find the age of metal ornaments and with diamond-drill bits we can drill into our past and bring out some concrete evidence.
And modern chroniclers depend on science rather than myths, so modern chronicles are more accurate.
And an essential point to be noted. Ordinary citizens of India started writing only under Mauryan rule. So more than 90% of Indian literature comes from orally transmitted stories, which varies as it passes from one tongue to another.
The stronger a light shines the darker are the shadows around it.