であること question

I read "であること" in a dictionary, under some explanation and I was wondering how can である be before こと?
From what I've read, である is like です、だ、でございます, but it's used for formal/neutral facts like in wiki.
As far as I know, all of the above can only be after nouns and at the end of sentences, or am I wrong?

Maybe I'm missing something about である, but it being used before nouns like こと、の、etc. seemed odd to me. Tons of examples here であることの英訳｜英辞郎 on the WEB：アルク

It happens that people want to form a relative clause of the type "A which is B". だ and です are not perceived as full-fledged verbs, and they cannot form relative clauses. (*BだA and *BですA are wrong). Instead, they are expended to で ある, which contains the regular verb ある and can form relative clauses: BであるA, eg 「父親である佐藤太清の絵画とその解説、自身の童謡の演奏や詩の朗読で構成された「こもりうたのように」コンサートを板橋区文化会館で開催。」

I see, thanks for the explanation.