It was the T-shirt heard around the World Wide Web.
Bluesky CEO Jay Graber made headlines this week for taking the stage at Austin’s SXSW wearing an oversized black tee. But it wasn’t just any Hanes or Uniqlo basic: The shirt was screenprinted with the phrase “Mundus sine caesaribus,” which is Latin for “a world without Caesars” — a clear dig at Meta CEO Mark Zuckerberg, who infamously wore a similar shirt referencing a Roman ruler at the company’s developer conference last year.
The shirt was a hit with Bluesky users (and Mashable readers). So on Thursday afternoon, Bluesky made Graber’s shirt available for purchase for $40 at worldwithoutcaesars.com, with all proceeds going towards the AT Protocol, the open standard its social network is build upon. The shirt sold out in 30 minutes, according to Emily Liu, Bluesky’s head of special projects.
Liu told Mashable that the company isn’t sure if it will restock the shirt just yet. We’ll update this story if another drop is ever announced.
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Graber’s shirt was a near copy of the one Zuckerberg donned for Meta Connect 2024 — same design, same typeface, but very different message. The Facebook founder’s original shirt read “Aut Zuck aut nihil” (“Zuck or nothing”), a spin on the Latin phrase “Aut Caesar aut nihil” (“Either Caesar or nothing”). Zuckerberg has seemingly spent several years chasing an obsession with the Roman emperor Augustus Caesar.
Mashable reached out to Meta for comment.
Mashable’s Chance Townsend reported that Graber doubled down on her anti-tech exec messaging in her SXSW keynote, emphasizing the value of open-source, decentralized platforms like Bluesky.
“If a billionaire tried to ruin things, [Bluesky] users could just leave — without losing their identity or data,” Graber said.
Bluesky launched in 2023 as an invite-only platform and quickly took off as an alternative to Elon Musk’s X. As of March 2025, it has over 32 million users.
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