The last remnant of the West Roman Empire was conquered in 486 when Clovis defeated Syagrius who had ruled over northern Gaul. That part of the Frankish kingdom would be called Neustria (the New Land) as opposed to Austrasia (the Eastern Land), which was the original core territory of the Franks.
Grab bar mounting brackets made specifically for fiberglass installation have discs that safely distribute the weight of a person and prevent the fiberglass from cracking. By attaching the brackets to wall studs with bolts, you ensure that the grab bar will not pull out from the tub or shower wall when in use.
Stand in the tub or shower and determine a comfortable height for the bar. Next, sit in the tub and determine the position where the bars are most helpful for getting in or out of the tub. Grab bars are equipped with flanges that are screwed to the wall with three hefty Phillips head screws. To ensure a solid installation, screw the bar into wall studs if possible. If this means adjusting the location of the bar a little, do it. Level and plumb don't count here.