The main purpose of the ARPANET was to develop a robust, fault-tolerant communication network for sharing research data among academic and military researchers. Established in 1969, it was the first operational packet-switching network and served as a precursor to the modern Internet. ARPANET's design facilitated communication across multiple nodes, enabling resilient transfers of information. Its successful implementation laid the groundwork for many of the protocols and concepts that underpin today's Internet architecture.