“Able was I ere I saw Elba.” – Napolean
Poetic as it may sound, “able was I ere” is not a sentence we may normally use, even if we forgive the archaism of the expression. When you introduce yourself to someone, it is customary to say ”My name is Thomas” rather than “Thomas is my name”. Grammatically speaking, there is nothing in particular that forbids you to say that. The verb ‘to be’ is a so-called copular verb, which means that it acts like an equal sign, signifying that the two nouns or adjectives surrounding it are equal (or at least that is the simplistic view). For an equal sign, then, which one of the two arguments comes first should not be a matter of concern, because they are, after all, equal. But we know that is not true.