Manhattan Portage started in 1983 in New York which is the city that is most synonymous with the bike messenger. The brand have been making various styles of messenger bag initially for bike messengers that were slowly picked up by the general public because of their usefulness.
Where they may have started out as bike messenger bags they now see use by a range of people because they can fit a good range of things in them. Each bag is well designed and durable and has a high level of functionality. In short they make good bags. Alpha Industries did a collaboration with Manhattan Portage for a three piece ultra tough capsule collection in suitable army-esque colours. Check those and the other bags out atManhattan Portage online.