To date, Putin has justified the invasion by saying, baselessly, that he's preventing Ukraine and what he described as a neo-Nazi government from committing genocide against ethnic Russians. He has also said that NATO's eastward expansion threatens Russia's national security.
Putin, speaking with students on Thursday after visiting an exhibition about Peter the Great, Russia's first emperor credited with making the country a major power in the early 18th century, compared himself to the ruler and said they were both destined to expand Russia.
"Clearly, it fell to our lot to return and reinforce as well," he said. "And if we operate on the premise that these basic values constitute the basis of our existence, we will certainly succeed in achieving our goals."
In addition to seizing territory in a 21-year war with Sweden in the late 17th century, Peter captured the territory of Azov from Crimean Tatars, who were aligned with Turkey, in 1696, and he seized territory on the Caspian Sea from Persia in 1723.
"On the face of it, he was at war with Sweden taking something away from it," Putin said of Peter. "He was returning and reinforcing, that is what he was doing."
In a tweet on Friday, Mykhailo Podolyak, an advisor to Ukrainian President Volodymyr Zelenskyy, said Putin's comments prove his "contrived pretexts of people's genocide" in Ukraine were false and demanded "immediate de-imperialization" of Russia.
Putin's attempts to expand Russian territory started long before his invasion of Ukraine on February 24.
Putin invaded Georgia in 2008 and still backs pro-Kremlin factions there. In 2014, Russia annexed the Crimean Peninsula from Ukraine and invaded the Donbas region of eastern Ukraine via proxies that same year.
Just two days before invading Ukraine, Putin said claims he wanted to restore the Russian empire were false.
But Western leaders have long maintained that this was not the case.
"He has much larger ambitions than Ukraine. He wants to, in fact, reestablish the former Soviet Union. That's what this is about," President Joe Biden said on February 24, the first day of the invasion.