Exactly how were the Spartans [HALO] defeated by the Covenant?

I'm having difficulty comprehending that a cloned genetically enhanced human could be defeated by the Covenant at the outbreak of the war. Master Chief was probably one of a handful of surviving Spartans by the time the war ended. So can someone explain how they were killed off? Were they massacred in one massive battle or just destroyed over the years?

Destroyed over the course of years. Something to keep in mind, is that despite all of the genetic mutations, Spartans are, actually, only barely equal with elites when it comes to speed and strength; they usually win mostly due to superior skill. That goes out the window when you're outnumbered 100 to 1 though, which is usually the case for Spartans in a fight.

So over the course of I believe 28 years (That's how long the war was), they were eventually just killed off; there weren't enough of them. There were 37 spartans from the SPARTAN-II program (which is the set that master chief is from), that fought in the entirety of the war. There are several billion covenant.

So, yeah. That's why they created the weaker but more numerous SPARTAN-III program. In Reach you play as a SPpartan-III.

Some of this might not be right though. I dunno as much as DarkC or Polaski do.

Originally posted by Darth Truculent
Master Chief was probably one of a handful of surviving Spartans by the time the war ended.

Actually I think by the end of the war Master chief was the last of the spartans, I don't remember there being any others but I think that a spartan III

Spoiler:
survived in reach

Chief is not the only survivor.

Who else is there?

http://halo.wikia.com/wiki/Spartan_II

Almost all of them that are MIA are actually dead. The UNSC doesn't declare dead spartans as KIA for morale purposes (spartans are supposed to be "immortal"😉, so instead of branding them dead, they brand them as missing.

There's at least one or two other Spartans besides Master Chief. At the end of Ghosts of Onyx, they were stuck in some kind of weird sphere inside a planet with Halsey, trying to find a way out.

It's been a long time since I've read that book, though, so this might not be fully accurate.

yeah linda fred and kelly are stuck in the dyson spear with dr. halsey on Onyx.

The Spartans were operating on Macs.

I've not read the books, but isn't it said in Halo (game) that Master Chief is the last surviving Spartan?