Insulated on three sides by desert and on the fourth by the Mediterranean Sea, a unanimous cultural identity developed that was unadulterated by outside influences and wholly subservient to the life-giving properties of the Nile, which formed the symbolic basis of its political system.
여기서 주절의 동사가 developed 인가요? 분사구문 insulated가 a unanimous cultural identity를 수식하고 that 이하에 unadulterated 랑 subservient 가 같이 was에 걸리는 것 까지는 파악했는데요,,, develop이 동사라면 that was는 어떻게 파악하는 것이 좋을지 모르겠어요!! 도와주세요ㅠㅠ 그냥 that이 접속사가 아닌 그것으로 쓰인건가요?