This was no mere bookkeeping oversight: Albo, Pigafetta, and the rest of the survivors erred because the international date line did not yet exist. No Western cosmologist or astronomer, not even Ptolemy, had anticipated that a correction would be necessary to compensate for sailing around the globe. It took the first circumnavigation to demonstrate the need for a twenty-four hour gain. By general agreement, the international date line now extends west from the island of Guam, in the Pacific Ocean.
