The gem of this castle complex is the old castle church, the Schlosskirche. Irish missionaries arrived here about 500 AD - a Carolingian church, think Charlemagne era, was built in 762 AD. This church probably dates from 900-1000 AD. S, but the square tower could be from the original church, ee ://www.sacred-destinations.com/switzerland/spiez-castle-church?source=ge
Early churches also served as refuges. Many had no windows, or very narrow ones at a higher height, not easy eye level, suitable for archers.
Frescoes inside Schloss Kirche, or the Castle Church, are faded - Christ Enthroned - but lighting is provided. Just put on the spotlights for yourself. Turn the lights out when you leave.
Narrow doors also were a defensive measure in many early castles and churches. Persons in armor had a difficult time passing through, and had to go single file. Meanwhile, on the other side, waited the ....
Dignitaries had to be accommodated.
Here, the Bishop's Chair, we believe. The enclosed foot and leg space would keep out drafts. No heating. Look at old pews as well - often high backed, with partitions and doors to the aisle.
But most of the oldest churches did not provide pews - just straw on the floor of a large milling-around area, where people stood, not sat. Later there may be individual chairs to move about.
Choir stalls, however, may have seating, including fold-up seats with little shelves you could arrange your behind upon, and look as though you were standing but you were really just butt-balancing. People in the choir and doing the services were not free to leave at any time. They needed support.
Crypt: Always ask for one. The crypt here was locked. Those tend to look alike, so we did not mind. Go down the old stairs, see the niches, the big coffin-holders, the sculptures on top of those within. Was this one different? We'll never know. In Germany, many crypts served as good bomb shelters.
This I hesitate to identify as part of the view from the Schlosskirche, because I am not sure. Is this later Murten, another town to the far west? Need to check. The Schlosskirche is on Lake Thun, with a lovely view of the little harbor there. Spiez or Murten? We think this is Lake Thun, despite the lower mountains to the other side. But the roof tiles look Murten. Will get back to you.