I think it is called 'call of the titans'? The spell that calls in all units not garrisoned in a city.

I am playing with latest updated game on large map and last night i decided to try this spell for the first time.

Initially i had decided to try and upgrade my sovereign as much as possible before marriage. So i rushed the adventure techs and tried to collect as many books as possible as quick as possible, but still, it was a hard slog.

Having various hero's scattered over the map, it is an extremely tedious task to get them all home and takes like, forever! So i decided to try that spell. It worked, except that all my caravans came along as well!! That is, deployed caravans that have already turned small have all been summoned and turned back into their large undeployed size!

Quite a useful discovery i think! because after i have created my road network, i usually have to hunt down all these caravans manually and delete them so i can redeploy according to best monetary outcome. Have you any idea how hard it is to find deployed caravans, especially the no cart ones or the ones hiding inside buildings! Needless to say, in future this spell will save me allot of effort!!