The Messenger Bag or a version thereof can be traced back to the Pony Express in the mid to late 1800s in the USA. Although different in style to todays Messenger Bags they were made of leather and used for carrying letters or ducuments. Able to be lifted of the pony these leather messenger bags had 4 small pouches for documents.
However earlier exploration of Messenger Bag types reveals for example a script bag from a Knight in 1244 jerusalem.
A 1645 New Model Army leather satchel / messenger bag.
And a 1916 Haversack / Messenger bag from the battle of the Somme.
So this simple and very practical type of bag has been around some time, and it is for a reason - it is hard to beat for versatility and practicality.
Messenger Bags in more modern times!
During WWII canvas messenger bags were used by medics and others due to their hard wearing properties and easy availability.
During the 1970s and 1980s in New York messenger bags were being more widely used by bicycle couriers, again due to the easy user friendly design. Easy to throw over the shoulder, with a waist strap for stability and quick access via the front flap for contents.
Todays Messenger Bags.
Today modern messenger bags can be made from a wide variety of materials including leather, cotton canvas, Waterproof Tarp / Tarpaulin, and Polyester amonst others.
Size and style vary greatly depending on the user requirements from A4 size document carriers to laptop computer messenger bags. With the great variety of styles there is also a crossover between what is perceived a messenger bag, a dispatch bag, as satchel or a briefcase. The more compact messenger bags have of late been called a Man Bag or Manbags.
Pros and Cons of the Messenger Bag
So what is the alternative - the backpack. Messenger Bags are ideal providing the weight carried is not too great, even with padded shoulder straps the weight of a messenger bag can begin to cause shoulder ache whereas with a backpack the weight is spread more evenly
With increased weight also comes increased instability, the backpack keeps the weight central for good balance whereas a the messenger bag can be a bit more unstable - partially solved by the introduction of waist straps which are a must for cycle couriers.
The pros of the messenger bag are its quick accessibility via the front flap, slim design if simply ferrying documents, multiple pocket variations and organizer sections for stationery, mobile phone etc.
The Messenger bag can be as casual a design as you like or be kept very professional looking with similar looks and style to a briefcase.