I can't find a previous thread specifically on the Blue Annals so I started this one.
The Blue Annals were written by Go Lotsawa Zhonnu Pel (1392-1481), a student of the fifth Karmapa Deshin Shekpa and Tsongkhapa. Go Lotsawa became abbot of Karmarning Monastery and was a teacher of the sixth Karmapa Thongwa Dönden.
The Blue Annals, completed in 1478, are an ecclesiastical history of Tibetan Buddhism focusing on the dissemination of the practice lineages throughout Tibet.
Here is a summary of the Blue Annals.
The Blue Annals in Tibetan from TBRC. You must first create an account to access the material.