Sometimes it is easy to answer, and sometimes it is impossible.
The reason: There have been a lot of watch manufacturing companies that have come and gone over the years.
Depending on the watch, only some of this information may be available; we only give out information when we have corroborating sources.
Antique and vintage watches can be defined as being over 100 years old or no longer in production and can be found at many jewelry stores, watch repair stores or online.
In the 1850's, Agassiz passed control of his company to his nephew, Ernest Francillon.
This method of production proved to be very successful, and by the early 1900's the Longines factory employed over 1000 people and had achieved worldwide distrubution and success with its products.
There are several websites that offer manufacture charts that provide the corresponding date of the watch, including Pinnacle Supplies, Brittons Watches and The Watch Guy (see Resources).
The ladies’ and men’s watches of the Longines evidenza collection draw their inspiration from that broad shift in habits and styles.These include A brief history and some of the serial numbers that some of the companies have used throughout the years.We can see that the grey dial is 06 and the black is 56, and if you look up to the previous Hydo Conquest we can indeed see that both of those black dialled watches have 56 in the dial colour position which fits in with what we leaned here.Wittnauer watches began with Albert Wittnauer, who created his brand of watches in New York in 1880.In 1936, the Wittnauer watch company joined with Longines watches and became the Longines-Wittnauer Co. As such, many vintage Wittnauer watches have serial numbers that are listed under the Longines Company.
The Longines "Winged Hourglass" (actually a winged clepsydra for those who care about such things) is the oldest registered trademark for a watch company, having been registered in 1880.