Donald Trump Jr.'s connections to Russia long preceded his recently-revealed correspondence with a lawyer connected to the Russian government in order to dig up dirt on Hillary Clinton.
As far back as 2008, Trump Jr. was on record bragging that "in terms of high-end product influx into the U.S., Russians make up a pretty disproportionate cross-section of a lot of our assets; say in Dubai, and certainly with our project in SoHo and anywhere in New York. We see a lot of money pouring in from Russia."
By 2011, according to a report by Politico, Trump Jr. had become a regular visitor to Moscow, and by 2013 he had established a friendship with Emin Agalarov, who hosted the Miss Universe pageant that year, was the son of real estate mogul Aras Agalarov and was a major pop star in Russia.
Soon Trump Jr. was in charge of a real estate project in Russia — namely, taking charge of and finding the right site for a Trump Tower in that country, according to a report by Yahoo News. That project ultimately collapsed after the Russian economy took a major hit due to the economic sanctions imposed by President Barack Obama in the aftermath of Russia's invasion of Ukraine.
Emin Agalarov, however, claimed that Trump's presidential run caused them to drop that idea. "But if he hadn’t run, we would probably be in the construction phase today."
Either way, by the time Trump Jr. was helping his father's presidential campaign in 2016, he was close enough to the Agalarovs that he was willing to trust them with sensitive information and requests on behalf of the campaign. Hence his receptiveness when he received an email from public Rob Goldstone saying "Emin just called and asked me to contact you with something very interesting."