Yes, and the Romans wanted their legionnaries to be 18 and farm workers. Though admittedly the legions did get the best medical care available (for what it was worth).
To resume my review...
The combat section of Mercator has a sailing-specific section which mentions distance, time and winds, both favorable and unfavorable. This is actually a good idea; I don't think I'd have thought of it. In addition, there are also rules for fire, boarding and so forth which can be easily added in to any game.
There are both sea and land encounters, with pirates and jackals and such, with the random encounters including commoners, barbarians and even wedding parties; a patron encounters section is included as well (merchants and Christians, oh my!).This is good, especially for lower-tech worlds; my wishlist for further encounters would be more types of animals and more random types of humans (and a fantasy version as well, for those who want a more mystical bent to their low-tech Traveller); the Classic sci-fi Traveller can be raided for such, since it has encounters that are a bit more low-tech than I'd expect for a sci-fi game: e.g. hunters and peasants, as opposed to taxi cabs and computer programmers. (What, a computer tech wouldn't put a hit out on somebody?!?)
The section following Encounters covers ports, such as Alexandria and Corinth, and provinces, such as Egypt and Greece. While the available ports and provinces are among the richest in the Roman Empire, and provide plenty of opportunity for trading and adventure, it is also is my source for complaint - I would actually be more interested in the Western Empire, such as Rome, Spain, Gaul and the author's native Britain. Also, I'd like more ports and inland cities on the map generally, just in case players say "I'd like to visit Judea, it's a lovely place, but JUST ONCE I'd like to avoid Caesarea!" And it'd be good to provide more color for the campaign, even if it's just news. Likewise, I would love to see other nations on the map - Persia, the German tribes and desert nomads are good examples. These would be excellent places for military or political campaigns. However, those areas which are mentioned are done well, albiet briefly (especially the comment about how Egyptians of the era are effectively slaves on their own ancestral lands...).
The equipment section covers weapons and armor - good thought on including shields - as well as tools, camping gear, lodging, food and sailing gear. It is well thought out except for a lack of horses and riding equipment (that and clubs being free; like in sci-fi Traveller, I'm sure that there are those who sell clubs for whatever the drachma version of 10 credits is).
In the end, I quite enjoy Mercator; it is an entertaining look at how to handle low-tech, non-fantasy Traveller. The author obviously knows a lot about the Roman period, and the available locations are well done. As I said, my main complaints about this are a lack of Western Empire and other inland locations and (what I feel is) an over-emphasis on sailing. That said, if ever I run a low-tech Traveller campaign, or even a sci-fi Traveller campaign, I shall utilize this, especially if someone in a sci-fi game wants to play a Barbarian (they aren't all tribal savages, you know!).
My suggestions for this would be: expand the equipment list, especially for non-sailing gear; have a section on horses and overland travel; add a way to differentiate non-citizens from citizens and from slaves (e.g. Soc 4 & 5 are free non-citizens, 6 + are citizens and 2 & 3 are slaves); finally, if someone, or groups of someones, were to write up a series of province books, e.g. Aegyptus Book, Hispania Book, Persia Book, including maps, ports, inland towns and such, I'd be happy (and would contribute, and would write up some NPCs and mythical creatures as well, as I've done already).