WASHINGTON (CBS SF/AP) — President-elect Joe Biden began his inauguration day Wednesday with a mass at The Cathedral of St. Matthew the Apostle officiated by Santa Clara University President Father Kevin O’Brien.

Father O’Brien, who has led Santa Clara University since July 2019, has been friends with the Biden family for nearly 15 years, dating back to when he was serving at Georgetown University.

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The mass was attended by over 100 family members and invited attendees including House leaders Speaker Nancy Pelosi and Kevin McCarthy and Senate leaders Chuck Schumer and Mitch McConnell.

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During his trip to Washington, Father O’Brien undertook numerous measures to prevent COVID-19 transmission, according to strict guidelines from the presidential transition team including wearing masks, social distancing, and other measures recommended by public health experts.

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He will quarantine for 10 days upon his return, following county guidelines.