See the popularity graph below for the name Theo? It's been heading straight uphill since 2010, when it hopped back onto the Top 1000 after a 60+ year absence.
 
Now in the Top 100 in this form, Theo's popularity is even wider given its common use as a nickname for Theodore, which made the Top 10 for the first time in 2022. This might be the generation of Theos.
 
Theo's newfound popularity extends far beyond the US and the rest of the English-speaking world. It's currently a Top 100 name in Germany, Brazil, Scandinavia, and beyond, as well as being a popular choice for pets.
 Theo first made an impact as the name of the only son on "The Cosby Show," earlier it was associated with Vincent van Gogh's supportive brother Theo.

Theo

A solid classic with plenty of history, Thomas strikes the balance between strength and gentleness. A favorite in the UK, a staple in France, and Australia, and never absent from the US Top 100, Thomas feels like a safe bet and a name that fits into any era. 
The Greek form of the Aramaic name Ta’oma, Thomas means “twin.” It came about in the Bible because there were too many apostles called Judas, and so, Thomas became the “twin”, to reflect his close brotherhood with Jesus. 
Known as “Doubting Thomas” due to his initial skepticism of Jesus’s resurrection, he went on to become a martyr, and there was no need to doubt Thomas’s potential as a given name. 
Brought into common usage by the Normans, it was then always among the 5 most common English names for boys at any point between the 13th and 19th century. 
While it has fallen down the US charts in recent years, it remains a familiar and trusted choice. Given to over 6000 boys every year, it has made a steady climb back into the Top 50. 
Across the pond in the UK, both Thomas and Tommy make the Top 30, while Tom, Tommy-Lee and Tommie have made their mark in the Top 1000. 
As a well-established classic, Thomas naturally comes with plenty of noteworthy namesakes. “Thomas the Tank Engine” might appeal to you kids, but there’s also the theologian, Sir Thomas Aquinas, the cardinal Thomas Wolsey, the Founding Father, Thomas Jefferson. the philosopher, Thomas Hobbes, and the writer, Thomas Hardy. 
More recent namesakes for those who aren’t into history include actors Tom Hardy, Tom Cruise, and Tom Hiddleston, singers Tom Parker and Tom Fletcher, Olympic diver Tom Daley, and Thomas Sanders, of YouTube fame. 
A timeless all-rounder, Thomas comes with the intuitive nicknames, Tommy and Tom, which feel sweet for a child but not too cutesy for a grown-up. For more unexpected options, you could try the nature-inspired Moss or Scottish Tam. 
Unlikely to go out of style anytime soon, Thomas is a refined but approachable choice. If the popularity does give you pause, however, you could try the surname-inspired Thompson, or an <a href=“https://nameberry.com/list/492/100-classic-boys-names--below-the-top-1000/all”> underused classic</a> like Marius, Rufus, or Phinneas. 
Alternatively, there is a wealth of interesting variants to ponder, from Italian Tommaso and Scottish Tavish to Croatian Tomo– and for girls, there’s Thomasina, Tomine and Tamsin.

Thomas

William is one of the most enduring of classic names for boys. It's also among the most popular boys' names, as American parents see it as being ideally conservative yet contemporary, and hands-down the most popular <a href="https://nameberry.com/search/boys-names/w">baby name beginning with W</a> of all time. 
 For 400 years, William has been second only to John as the most popular name in the English-speaking world. And now of course, it's also a newsy name—thanks to Britain's high-profile Prince William.
 William is derived from the Germanic name Wilhelm, composed of the elements wil, "will," and helm, referring to a helmet or protection. The name was introduced to England by William the Conqueror, with William being the Norman variation of the name. In Central and Southern France, it was translated as Guillaume.
 
In terms of short forms, yesterday's Bills and Billys have given way to today's Wills—or Williams, with no diminutive—though a few hip Billys, including Helena Bonham Carter and Tim Burton's, have surfaced recently. 
 But Irish spinoff Liam is the most stylish William nickname and has now superseded William, becoming the most popular boy name in America. Riding the William bandwagon is the Dutch Willem, which comes with the unique nickname Pim.
 
William has long reigned as a royal name in the U.K. There are tons of worthy namesakes called William, including William Shakespeare, Bill Gates and four U.S. presidents.

William

samjaymc's list "His Royal Highness (Boy)" of 3 great name ideas: Theo - William!

His Royal Highness (Boy)

Favourite boys names, including current crushes that may be deleted within the future.

His Royal Highness (Boy)

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