Max von Laue was the first to study the problem of the consistency of Einstein's synchronisation. Ludwik Silberstein presented a similar study although he left most of his claims as an exercise for the readers of his textbook on relativity. Max von Laue's arguments were taken up again by Hans Reichenbach, and found a final shape in a work by Alan Macdonald. The solution is that the Einstein synchronisation satisfies the previous requirements if and only if the following two conditions hold: