The progression of the mammillary axonal complex over time, from its formation to the mature structure. The mammillary axonal complex is formed by the axons from the lateral, medial mammillary and the dorsal premammillary nuclei which share a branching pattern. Every neuron gives off one axonal stem that bifurcates into 2 branches. One of the branches is directed dorsally to the thalamus and another caudally to the midbrain.