The goal of braille uniformity is to unify the braille alphabets of the world as much as possible, so that literacy in one braille alphabet readily transfers to another. Unification was first achieved by a convention of the International Congress on Work for the Blind in 1878, where it was decided to replace the mutually incompatible national conventions of the time with the French values of the basic Latin alphabet, both for languages that use Latin-based alphabets and, through their Latin equivalents, for languages that use other scripts. However, the unification did not address letters beyond these 26, leaving French and German Braille partially incompatible and as braille spread to new languages with new needs, national conventions again became disparate. A second round of unification was undertaken under the auspices of UNESCO in 1951, setting the foundation for international braille usage today.