The Greece international, who was also wanted by Arsenal, had his heart set on a move to the Stadio Olimpico and is unperturbed by the prospect of replacing Mehdi Benatia.
Premier League outfit Arsenal tried to sign the Greece international but the Gunners' 10 million euro bid was rejected by Olympiakos.
Manolas has now claimed, though, that the Serie A champion was also interested in his services but that the Bianconeri never had any chance of persuading him to move to Turin instead of Rome.
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"I had numerous offers from big clubs, including Juventus," the defender told reporters after being unveiled as a Giallorossi player on Wednesday. "But it was my choice to come here. I wanted to come to Roma.
"Many people have spoken highly of this club to me and their advice, as well as my own thinking, carried me here."
Manolas' arrival in the Italian capital came just hours after Mehdi Benatia had departed to complete his move to Bayern Munich.
The Moroccan was one of the key factors in Roma's remarkable second-placed finish in Serie A last season but Manolas is undeterred by the prospect of having to replace such a highly-rated center half.
"He is a very good player, but he represents the past, I'm the present," the 23-year-old declared. "I don't know if I will be a starter. I will give my best to merit a place. Will I play right away? The coach will decide that. But I'm ready. I'm not at 100 per cent, but 120 percent!"