What is the real history of Kayastha Community?

There is a lot of mythological text regarding their origin or route but I wanted to know the geographical migration routes of them since I believe they are scattered all around North and Central India. Also which texts are available to us keeping description of this community? Also does anyone have account of their migration patterns? Please do not take this question for any other way and provide the knowledge they themselves have, I think there are family kept stories about theor individual families migration, that too I would be more than happy to read since I think there is a lack of collective data on it and lack of research too. Also, if anyone knows about their family tree beyond more than general knowledge please do share their history if they like because that would be really interesting to read.