The first ~10 Myr of Solar System history was a period of intense proto-planetary evolution amenable to investigation in the laboratory due to sampling via the natural delivery of meteorites to the Earth from the asteroid belt. Meteorites indicate that an enormous diversity of proto-planetary bodies formed in the first few millions of years. The most commonly found, the chondrites, are brecciated sedimentary rocks from bodies accreted in the solar nebula, which evolved little further. Many chondrites, such as the ordinary (H, L, LL), chemically reduced enstatite (EH, EL), and some oxidised clans (R, CK), underwent various degrees of thermal metamorphism driven by decay of radioactive 26Al while inside their respective parent bodies. Despite this, the chondrite classes preserve a range of compositions reflecting nebular conditions and fractionation events, arising due to different volatilities and the lithophile, chalcophile or siderophile behaviours of elements, and mineralogical differences related to oxygen fugacity (fO2) spanning many orders of magnitude.