In mediaval times, the trades were controlled by guilds, which classified tradesmen as either apprentices, journeymen or masters. To gain admission to the guild as a master, tradesmen had to submit a piece of work -- a "masterpiece" -- which showed that they had achieved the level of formal, technical skill and knowledge to be considered a master. These were usually standarized items too. For example to be admitted to the guild of woodworkers, candidates were perhaps all expected to design and build fancy and creative tool cabinets.
I know that a comparison of tradesmen with artists may be imprecise, but I often wonder how this would apply to artists in general and photographers in particular. Unfortunately I am not sufficiently familiar with the development of the works of famous photographers over the course of their careers to be able to determine when they were judged to have crossed that line between journeymen and masters, but I suspect for example that in the case of Mapplethorpe, his flowers were his masterpiece even though he is better known for his erotic photography.
If anyone can provide some insights on the works of other famous photographers, which are considered to mark that time in their career when they were deemed to have become masters rather than journeymen, I would appreciate it. Or, how about yourself and your own work?