St Peter’s Basilica, in its current form, is about 400–420 years old, depending on whether you count from completion or from its dedication.

Quick Scoop

  • Construction of the present St Peter’s Basilica began in 1506 under Pope Julius II.
  • Major building work was essentially completed between 1615 and 1626.
  • The basilica was solemnly dedicated on 18 November 1626 by Pope Urban VIII.

So, as of 2026:

  • From the start of construction (1506): it is about 520 years old as a project.
  • From completion (around 1615): it is about 410 years old.
  • From dedication (1626): it is exactly 400 years old in 2026.

You can think of it this way: the “current” St Peter’s is an early 17th‑century church built on a 4th‑century site, so the site has been sacred for more than 1,600 years, but the present basilica itself is about 400 years old.

SEO-style meta description:
St Peter’s Basilica in Vatican City was built between 1506 and 1626, making the present church about 400 years old in 2026, on a Christian worship site dating back to the 4th century.

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