 "Minchah Gedolah" (מִנְחָה גְּדוֹלָה, literally the greater Minchah), one-half variable hour after midday, is the earliest time to recite Minchah, although one should try, if possible, to wait until Minchah Ketanah (literally the smaller Minchah).On Yom Kippur, the congregation "must" begin Mussaf by this time, because otherwise they would be required to pray the more frequent prayer (Mincha) first.