Quote from: worldofcoins on Today at 07:12:20 PM

But was there any such attack on Bitcoin around that time?

Bitcoin can be possibly hit by 51% attack that time but there's no evidence that it was experienced such attack. We know that they can afford the hashing power before if we compared it today.

The current level of Bitcoin hash rate is around 437.01M TH/s and the 51% is 222.9M TH/s. The best Bitcoin miner which is Antminer S19 pro only has 110 TH/s and it cost 3000$ for one. Imagine, you have to get 2M Antminer S19 pro in order to make 222.9M TH/s, which is around $6B and that's too expensive. I think there's no bad organization want to take risks on that.

https://ycharts.com/indicators/bitcoin_network_hash_rate#
https://www.investopedia.com/terms/1/51-attack.asp