Wallacean islands are interesting because they have rarely, if ever, been connected via land bridges to either the Asian continent to the west or the Greater Australian continent to the east.
This longstanding separation from the surrounding continents has severely limited the ability of animal species to disperse either into or away from the Wallacean islands.
For example, Christian time counts the birth of Christ as the beginning, AD 1 (Anno Domini); everything that occurred before Christ is counted backwards from AD as BC (Before Christ).
Prior to the development of radiocarbon dating, it was difficult to tell when an archaeological artifact came from.
Unless something was obviously attributable to a specific year -- say a dated coin or known piece of artwork -- then whoever discovered it had to do quite a bit of guesstimating to get a proper age for the item.
Also, the larger the sample the better, although new techniques mean smaller samples can sometimes be tested more effectively.
The data can be a little off particularly in younger artifacts, and anything older than about 50,000 years is pretty much too old to be tested because at that point the majority of the C-14 has decayed to practically undetectable levels.