Complex sentence: As a notorious example of how such errors can become officially established, the extant and established name of Nome, Alaska allegedly originated when a British cartographer copied an ambiguous annotation made by a British officer on a nautical chart.
Split into simpler sentences: As a notorious example of how such errors can become officially established, consider the extant and established name of Nome, Alaska. Allegedly it originated when a British cartographer copied an ambiguous annotation made by a British officer on a nautical chart.