Erasmus was the one who introduced the "Johannine Comma" (1Jn 5:7), which came from a few Greek manuscripts he discovered:
"Erasmus primarily used a small number of relatively late
Byzantine Greek manuscripts for his Textus Receptus.
The Johannine Comma, found in 1 John 5:7-8, is a controversial passage present in some Greek manuscripts, but not the majority. While absent from the earliest and most important Greek manuscripts, it appears in a few later ones, primarily as additions to the text. These include manuscripts like 629, 61, 918, 2473, and 2318. The passage is also found in some Latin manuscripts and was included in various printed editions of the New Testament, notably those based on the
Textus Receptus." ---Google AI
All Bible translations derive two primary manuscript sources: The Majority Text and the Minority Text. The Majority Text contains the majority of manuscript copies, which number around 3,500 copies. The Minority Text has only three primary sources (called the Eclectic copies) which include the Vaticanus manuscripts, the Sinaiticus manuscripts and the Alexandrinus manuscripts.