I'm going to disagree with Mariah a little here. "Beloved of all" and "beloved by all" are correct and would be understood. They also mean exactly the same thing. They are not necessarily strange (especially to an old guy like me), but they are falling out of use (obviously) by the younger English speakers. You would also see in more in written English - almost never in spoken English. It is usually found in older stories and fairy tails - "The princess was beloved by all". You would see "beloved by" much more than "beloved of" - the second one is very old and almost never used, but would still be understood.

Hm, the word 'beloved' seems like it should be changed to just 'love'. If you do that, you can say: He was 'loved by' all. - This would mean that everyone loved him. (beloved still means that a person is loved a lot but it sounds a bit weird in this sentence)