The three main phases of a single cell cycle are: interphase, nuclear division and cytoplasmic division.
With the right techniques, the next stage in the cell cycle, mitosis (M), can be observed using a good light microscope. Early microscopists found it convenient to subdivide the nuclear division of cells into stages that were easily seen under the microscope using colored dyes that stained the chromosomes and some of the other participants.
Nuclear division or karyokinesis is a continuous process, however, and there are no artificial divisions in actively growing cells.
prophase - metaphase - anaphase - Telophase
Telophase overlaps with beginning of cytoplasmic division. Spindle fibers vanish as quickly as they appeared and the chromosomes begin to unpack themselves, and become less and less visible to staining with dyes.
As the chromosomes diffuse out, exposing their DNA, new nuclear membranes begin to form around them, separating them from the cytoplasm of the cell and allowing the start of RNA synthesis (for interphase) once more. One or more nucleoli may now reappear.
These events overlap with the important division of the cytoplasm of the original cell, the distribution of its organelles and contents, and the physical separation of the original cell into two halves; cytokinesis.