By the 14th century, the incongruity was avoided via the concept of Limbo, the abode of righteous souls who weren't destined for either Heaven or Hell. In particular, babies who died in childbirth or those who died before the time of Christ, would have had no choice but to remain unbaptized. Theologists, especially those of the Roman Catholic persuasion, were much exercised by the fate of those who, while not being sinners to be condemned to Hell, were unbaptized through no fault of their own. Mediaeval Christian belief had it that only those who were baptized into the Christian Church could enter Heaven.

Limbo was originally a place rather than a dance. People had been in limbo well before the 1950s, of course. There's no definitive documented link between limber and limbo, but it seems very probable that they are actually versions of the same word. The adjective limber has been in use in English since the 16th century, with the meaning 'pliant and supple easily bent'. The craze was created, or the uncharitable might say, cashed in on, by Chubby Checker, who released the single Limbo Rock and the album Limbo Party in 1962. This originated in the West Indies around the 1950s and became something of a fad in the 1960s. Limbo is now most often associated with the form of party dance, in which dancers bend backwards and shuffle under a horizontal stick without touching it.

Being in limbo phrase