908. King Solomon Created Eiruvin
Eiruvin 1:3
People who live in tents, booths or an encampment surrounded by a partition may not carry from tent to tent unless they make an eiruv. Conversely, members of a caravan surrounded by a partition do not require an eiruv and may carry from tent to tent. Their situation is already considered to be an eiruv by virtue of its temporary nature.
Eiruvin 1:4
King Solomon enacted the rule of eiruv so that the people would not err, thinking that just as it is permitted to carry from courtyards to streets in a city and to carry to a courtyard, it must likewise be permitted to carry from a city to the fields and vice versa. They would further err, assuming that marketplaces and streets - public domains - are like fields and deserts, causing them to assume that only courtyards are private domains and that there is no prohibition against transferring between domains.