Sinaiticus has an older brother. Codex Vaticanus. :)
Codex Vaticanus
https://en.wikipedia.org/wiki/Codex_Vaticanus
The manuscript is believed to have been housed in Caesarea in the 6th century, together with the Codex Sinaiticus, as they have the same unique divisions of chapters in the Acts. It came to Italy – probably from Constantinople – after the Council of Florence (1438–1445).[84]
The manuscript has been housed in the Vatican Library (founded by Pope Nicholas V in 1448) for as long as it has been known, appearing in the library’s earliest catalog of 1475 (with shelf number 1209), and in the 1481 catalog. In a catalog from 1481 it was described as a “Biblia in tribus columnis ex memb.”