In a parish church, about the same time: just under an hour. Here's a very interesting web site, ["The Experience of Worship"] (http://www.experienceofworship.org.uk/) that offers very detailed information about what a late medieval mass in England would look like with historically informed video reenactments of services at St. Teilo's parish church and at [Salisbury Cathedral] (http://www.experienceofworship.org.uk/enactments/jesus-mass/mass-of-the-holy-name-salisbury/).