Bitcoin's journey from a theoretical concept to a global phenomenon is one of innovation and intrigue. The origins of this digital currency can be traced back to October 2008, when an anonymous figure known as Satoshi Nakamoto published a whitepaper that would forever change the landscape of finance and technology.

In this seminal paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System," Nakamoto proposed a decentralized digital currency system based on cryptography. The concept was groundbreaking at the time, as it aimed to solve the inherent problems with traditional banking systems by eliminating the need for intermediaries and providing a secure ledger of transactions that could be trusted without relying on any central authority.

The foundation laid in this whitepaper was not immediately recognized or acted upon until January 3, 2009. On this day, Satoshi Nakamoto mined the first block in Bitcoin's blockchain – an irrefutable ledger of all transactions ever made within the Bitcoin network. This block is known as the Genesis Block or simply Block 0, marking the official launch of Bitcoin and its corresponding digital currency.

The genesis block was a pivotal moment not only for the birth of Bitcoin but also for the nascent field of cryptocurrencies. It signified that Nakamoto's vision had been realized, and from this point forward, Bitcoin could function as a legitimate medium of exchange. However, the journey of Bitcoin did not stop at its launch; it was followed by numerous milestones and challenges over the years.

In 2010, one of the most notable events in Bitcoin's history occurred when programmer Laszlo Hanyecz purchased two Papa John's pizzas for 10,000 bitcoins. This transaction is often considered as the first successful use of Bitcoin as a real-world currency, highlighting its potential as an alternative to traditional fiat currencies.

Since its inception in 2009, Bitcoin has experienced significant fluctuations in value, regulatory scrutiny, and technological advancements. The blockchain technology underlying Bitcoin has not only made it more secure but also more efficient in terms of processing transactions. This innovation led to the creation of other cryptocurrencies that built upon the foundational elements established by Nakamoto's groundbreaking work.

The early years of Bitcoin were marked by its acceptance within a small, yet passionate community of enthusiasts. However, as the value and popularity of Bitcoin soared, it began attracting mainstream attention. Media coverage, regulatory bodies' involvement, and even governments acknowledging cryptocurrencies as a legitimate form of currency have all played roles in shaping Bitcoin's reputation over time.

As we continue to navigate through this digital era, Bitcoin remains an integral part of the evolving landscape of finance and technology. Its journey from a revolutionary concept discussed among cryptographic experts to a widely accepted medium of exchange highlights its potential as both a financial tool and a new frontier for economic exploration. The future holds many uncertainties for Bitcoin, but one thing is clear: Satoshi Nakamoto's initial vision has not only been realized but has also inspired countless others to dream big in the world of cryptocurrencies.

In conclusion, when discussing "when did Bitcoin first start?", it's essential to acknowledge that the journey began with a vision articulated in 2008 and came to fruition on January 3, 2009, with the creation of the Genesis Block. Since then, Bitcoin has evolved from an obscure idea into a global phenomenon, showcasing its resilience, potential, and impact on our financial systems.