Short answers, pulled from the story.
Chinese sources from the sixth century attribute the work to an Indian named Sāramati, also known as Jianyi or Suoluomodi. This attribution first appeared in the writings of Zhiyi, a prominent scholar of that era.
Ratnamati brought a Sanskrit version of the text to China in 508 CE and translated the entire text into Chinese at Luoyang in 511 CE. This translation shows the complete text existed in India during the early sixth century.
The text organizes its doctrinal content around seven main topics called vajra points which describe Buddha, Dharma, Sangha, dhātu, bodhi, buddha qualities, and Buddha activity. These topics explain how all sentient beings possess a permanent Buddha element even though it remains covered over by defilements.
Late Indian Buddhist scholars Jñānaśrīmitra and Ratnākaraśānti cited and commented on passages of the text while preserving works like Mahāyānottaratantraśāstropadeśa by Sajjana. Various interpretations developed within Tibetan Buddhism including nonimplicative negation views influenced by Madhyamaka schools such as Gelug and Sakya.
Fazang, key patriarch of Huayan school living from 643 to 712 CE, highly esteemed the work and his theories rely thoroughly on the treatise. The text also impacted Paramārtha, Mahayana Awakening of Faith, Sanjie school, Wonhyo, and Japanese authors Juryō and Chikei of Nara Japan between 710 and 784 CE.