ちょうどそこに誕生寺という寺がありました。日蓮の生れた村だから誕生寺とでも名を付けたものでしょう、立派な伽藍でした。
How do you parse the second sentence? I asked this question a while back, but I think it might be different this time.
I think it says "Right over there, there was a temple called the birth temple. They probably called it that because Nichiren was born in this village, and it's an elegant temple."
Or does the "deshou" clause actually modify 伽藍? Maybe it's like "It's an elegant temple that they probably named that way because Nichiren was born in this village."
Also what does もの refer to?