Houpelands are generally dated as being between 1350 and 1450.
They were definitely known in England from the 1380s, and Europe from the first half of the 15th century
Today's formal academic and legal robes are thought to be a remnant of this style.
What is this? This is The Garbindex - a guide to making garb for recreationists (ie how to sew clothes that will make you look genuinely medieval, when 'playing' with such groups as the SCA, doing LARP - or even making something really genuine for drama.)
Use these resources to find resources that will help you create clothing that looks great - and real!