Here is a section of a map from 1823, it shows the buildings built on top of that, note the circular shape:
Same map browsable here, change the opacity on the top right to see current aerial photo.
According to some legends it was used as a fort in the middle ages, bu afaik no archeological remains support this.
Another map from 1878, with more details, it shows the contours of the buildings:
Wdym spyware? Isn't the stock dialer comes from aosp and it's open source? Or your rom doesn't use that one?