First Age 366
First Age 366 (abbreviated to F.A. 366) is the 366th year of the Sun of the First Age of Middle-earth.
Notable events in this year include:
J.R.R. Tolkien, Christopher Tolkien (ed.), The War of the Jewels, "Part Two. The Later Quenta Silmarillion: Of the Coming of Men into the West (Chapter 14)", p. 237