谁能给解释解释这里为什么要用过去完成时？

jennyguoguo

Opened in 1683, the Ashmolean was the first public museum in Great Britain,
just as earlier the Bodleian had been the first truly public library.

joywzy

A is predated by the public library , thus using past perfect tense.

linlin315

过去完成时就是过去的过去
这句的意思是A是first public museum，用的是was说明已经是过去了
就像earlier的B是the first truly public library一样。说明B是在A以前的，不正好是过去的过去吗？应该用过去完成时！！