Before becoming a mom herself, Markle was an aunt to Louis and his siblings, George and Charlotte, which means the youngest member of the Cambridge family has several relatives through the Duchess of Sussex, though they aren't related by blood.
Markle's parents, Thomas Markle and Doria Ragland, are Louis' great-aunt and uncle, though it's unlikely that Louis will meet Thomas, as he and his daughter currently have a strained relationship. The Duchess of Sussex also has two half-siblings, Thomas Markle Jr. and Samantha Markle, neither of whom she has a relationship with.
On his mom's side, Louis has grandparents Michael and Carole Middleton and aunt Pippa Middleton and brother James Middleton. Louis is also a cousin to Pippa and husband James Matthew's son, Arthur. Louis' paternal grandfather is Prince Charles, while his great-grandmother is Queen Elizabeth II and his great-grandfather is Prince Philip.
Louis and his aunt Meghan recently spent time together at the King Power Royal Charity Polo Day, with the toddler and duchess on hand to watch William and Harry play on opposing teams at the Billingbear Polo Club in Berkshire.
Royal correspondent Rebecca English called the event "royal baby heaven" on Twitter and shared that Louis had to be chased down by his mom after he made a break for the horses. George and Charlotte also found themselves polo mallets and enjoyed a bit of soccer together.
In a highlight of the day, Louis stole his mom's sunglasses and wore them himself, making a royal fashion statement along with his navy polo and green shorts. He also stuck out his tongue, because he's 1 year old and hilarious.
Baby Archie was also in attendance at the match, and the outing was the first for the royal cousins as George, Charlotte and Louis had not attended Archie's christening the week prior.
Photo Credit: Getty / Karwai Tang