Prophase

Discounting interphase in meiosis, it is the first phase of three parts (early, mid and late) of cell division in which chromosomes contract and divide along their length into chromatids, except for the centromeres.  By late prophase, the two chromosomes begin to move apart and align in pairs as the nuclear membrane has already broken apart. 

See Anaphase, Centromere, Chromatid, Chromosome, Interphase, Meiosis (or reduction division), Metaphase, Teleophase