Why are there duplications of pre-1856 events in the NSW Indexes?

The NSW Registry was established in 1856. When created, the Registrar at the time ordered the indexing of events prior to the Registry's establishment.

Records of Baptisms, Burials and Marriages were obtained from the various denomination's archives and recorded in the NSW Registry.

The Registrar also recorded some records held in various parishes as well. This was a duplication of what was already held in the denomination's archive hence the duplication of events given different index numbers.

The rule-of-thumb is aim for the record with the highest volume number.