The narrowness of bridges combined with the fact they cross a long linear obstacle has always made them a place which is defensible. However a number of medieval bridges had gates in gatehouses, either on the bridge itself, or at one end of the bridge, which made these bridges fortified. Some also had drawbridges, although in some cases these may have actually been raisable bridges to allow masted vessels to pass under the bridge. In practice it may be these gates were mainly gates to control traffic and ease the collection of tolls and many bridges had simple bar gates for such a purpose. A number of bridges also had chapels or even hospitals (probably in the medieval sense of visitors lodging houses) on them which, again, may have had a role in toll collection. The toll may also have been taken as a 'voluntary' charitable donation.