When was envy from fullmetal alchemist born?

Envy, from the Fullmetal Alchemist series, doesn't have a specific birthdate. He is a Homunculus, an artificial being created by the Father using alchemy. His creation is connected to the events surrounding the "Ishvalan War" and the "Father" attempting to achieve a perfect world.

However, we can pinpoint the "beginning" of Envy's existence to sometime between the events of Ishvalan war (which started in 1911 in the series' timeline) and 1915, when the events of the first Fullmetal Alchemist anime/manga begin. This period is when the Father was actively creating the Homunculi.

Therefore, while we don't know the exact date of his birth, we can place it within this timeframe.