Bitcoin is considered the "king" of cryptocurrencies for several fundamental reasons:

1. First in Class
Bitcoin was the first decentralized cryptocurrency, created in 2009 by a person (or group of people) under the pseudonym Satoshi Nakamoto. Its launch marked the beginning of the cryptocurrency era and laid the groundwork for the development of other digital currencies.

2. Increased Market Cap
Bitcoin has the highest market capitalization of all cryptocurrencies, meaning it is the largest and most valued cryptocurrency in terms of its circulating supply and price.

3. Wide Acceptance and Adoption
Bitcoin has been widely adopted as a form of payment and as a digital store of value. Numerous online and brick-and-mortar merchants accept Bitcoin as a payment method, and more and more individuals and institutions are investing in Bitcoin as a digital asset.

4. Network Security and Robustness
The Bitcoin network is one of the most secure and robust in the cryptocurrency space, thanks to its underlying blockchain-based technology and the amount of computational power dedicated to Bitcoin mining.

5. Scarcity and halvings Bitcoin has a limited maximum supply of 21 million coins, making it scarce and potentially valuable in the future. In addition, Bitcoin's halving process halves miners' rewards from time to time, contributing to its scarcity and appreciation.

In short, Bitcoin is considered the "king" of cryptocurrencies due to its pioneering position, wide acceptance and adoption, high market capitalization, security and robustness, and unique monetary scarcity and programming.