Although the timeline of the games is generally kept vague, there are some clearly defined time gaps between the X series and the ZX series. I'll list those gaps for discussion and to hopefully, give us more insight on the nature of the setting.

Keep in mind: this is not RP canon. It's more of a guideline, or food for thought, if you will. You don't need to read this topic to play in the RP, where we actually refrain from specifying the time period. If you do, however, you might have an idea of how much the world has changed up to the present point of the RP.

This post can be updated as I obtain more information. I may also include licensed products when applicable.

Timeline:

• Mega Man X's awakening: Year 21XX
• X-Hunter incident: Six months after X's first victory against Sigma.
• Revenge Limited incident: Two months after the DopplerTown incident.
• Nightmare incident: Three weeks after the start of the Earth Crisis.
• Zero's stasis: Year 22XX+
• Sigma Virus experiments on Zero: 50 years.
• Elf Wars: 4 years.
• Zero's second stasis and awakening: 100 years later.
• Dark Elf incident: One year later.
• Dr. Weil's return: Two months later.
• Ragnarok incident: Eight months later.
• Vile's Incident: Two years later.
• Serpent incident: 200 years later.
• Rise of Ouroboros: 4 years, 8 months after the Serpent incident.

Results:

Time estimate: At least 448 years, 6 months (2114 as the base year, and 22XX as 2200).

Possible year: At least 2562 (25XX - 26XX)

Possible year in Mega Man ZX Expansion: At least 2558

References:

• "NOM ENGINEER WORK SYSTEM Model CPS-9204 Copyright (c) 2105, 2109, 2114" -- Dr. Cain's computer, Mega Man X; used to determine base year.
• "If there is no problem... It will be around August 15th, 102 years from now." -- Scientist in Zero's ending, Mega Man X6; this reference is not used above due to the circumstances that would upset this estimate.
• There are resouces stating that several months pass between certain MMX games; this needs to be verified.

Mega Man X2 states that it takes place six months after Mega Man X, but with the seemingly drunken ass monkey of a translation... Well, who knows.

All I know is that X6 retconned X5's 3 year difference to 3 weeks between games, which is almost a month between X5 - X6.

I believe Command Mission gave an actual year for when Giga City's Meteorite fell which was like 2202 or something.

"2202XA8" is the name of the planet Force Metal originated from. It isn't a time period.

Somebody told me that there was a date given but I wasn't sure. But okay.