I think almost all supply voltages go back to multiples of 50 to 55 V, the typical operating voltage of a carbon arc lamp. Depending on how many lamps were wired in series and how much the designers trusted available isolation materials the supply voltage was chosen. As soon as the move from local generators to larger central power stations started, system voltage became a compromise between voltage drop on the one hand and safety and available isolation materials on the other.
Almost all post-1900 electrification schemes in continental Europe settled for 50 Hz AC with large power stations and 220/380 V 4-wire local distribution. Exceptions were usually related to individual projects with particular needs, e.g. the electrification of the Mariazell railway in 1910, at the same time supplying 25 Hz electricity to adjacent homes and businesses. Here the frequency was chosen because of railway engine design issues (AC motors up to about 25 Hz can be controlled like DC motors using series resistors).
This is just a personal suspicion, but I'm almost convinced that 127/220 V systems were mainly installed to replace 3-wire DC systems without messing with the wiring.
