Gears Of War Fanon:Seran Calendar

Overview
The Seran Calendar is the way in which the date is written and recorded.

The Seran Calendar is mostly identical to the calendar we use, except for the way that years are measured. Where we have BC and AD, and the year 0, Serans measure time by the passing of Emergence Day. Years are measured as BE and AE (Before Emergence and After Emergence respectively). The higher the year in BE, the further in the past the year occured, whereas the higher the year in AE, the more recent the year is.

Relevancy to the Gears Of War games
This means that (going by the calendar) Marcus Fenix thought the Locust from 0AE through to 10AE, at which point he attempted to save his father, and was incarcerated. Four years later, in 14AE, he is freed from prison, and the events of Gears of War 1 begin. Gears of War 2 takes place around half a year after GoW 1, and so likely takes place in 14 or 15AE.