Light patch in the night sky
Given the description, that light patch was probably Pleiades.



It is a star cluster in the constellation of Taurus which is inspired from a popular Greek mythology of Seven Sisters. You can read more about it here.

EDIT: One of the great softwares, free and open source, for amateur level observational astronomy, though professionals use it as frequently is Stellarium. It's easy to use and should clear all your doubts.