As I discuss in this question, one of the early movements that was important to the development of Vaishnavism was the ancient Pancharatra movement, whose sacred texts consisted of detailed procedures to worship the sage Narayana, an ancient incarnation of Vishnu. The Pancharatra movement eventually merged with the Bhagavata moevemebt, which worshipped four forms of god (Vasudeva, Sankarshana, Pradyumna, and Aniruddha), and then the followers of this combined movement realized that it was no coincidence that the Bhagavata deities share the names of Krishna, his brother Balatama, his son Pradyumna, and his grandson Aniruddha. And then when it was realized that Krishna was an incarnation of Vishnu, Vaishnavism as we understand it today was born.
In any case, among the oldest Pancharatra texts are the Satvata Samhita, the Paushkara Samhita, the Ahirbudhnya Samhita, and the Jayakhya Samhita. But there's another Pancharatra text that is popular among Gaudiya Vaishnavas, the Brahma Samhita. Chaitanya Mahaprabhu, the 16th century Vaishnava thinker and founder of Gaudiya Vaishnavism, is said to have discovered this text in the Adikesava Perumal Vishnu Temple in Tamil Nadu. Here is how the Chaitanya Charitamrita, the standard account of Chaitanya Mahaprabhu's life, describes it:
In the temple of Adi-kesava, Sri Caitanya Mahaprabhu discussed spiritual matters among highly advanced devotees. While there, He found a chapter of the Brahma-samhita. Sri Caitanya Mahaprabhu was greatly happy to find a chapter of that scripture, and symptoms of ecstatic transformation -- trembling, tears, perspiration, trance and jubilation -- were manifest in His body. There is no scripture equal to the Brahma-samhita as far as the final spiritual conclusion is concerned. Indeed, that scripture is the supreme revelation of the glories of Lord Govinda, for it reveals the topmost knowledge about Him. Since all conclusions are briefly presented in the Brahma-samhita, it is essential among all the Vaishnava literatures. Sri Caitanya Mahaprabhu copied the Brahma-samhita, and then with great pleasure He went to a place known as Ananta Padmanabha.
You can read the Brahma Samhita here; only chapter 5 of it survives, although it's claimed that it was originally 100 chapters long. Western historians generally claim that due to the style of the language, it's likely a relatively late text.
My question is, what is the earliest reference to the Brahma Samhita? Are there any records or scriptures dating back to before the time of Chaitanya Mahaprabhu which mention this text?