Prince Charles turns 71: Sons Prince William, Prince Harry wish 'Sir, Pa, Grandpa' a happy birthday

Prince Charles turned 71 on Thursday, and his royal family wished him well on social media.

The Prince of Wales received birthday messages from sons Prince William and Prince Harry on Instagram, plus from his mother, Queen Elizabeth II, and from his brother, Prince Andrew, Duke of York, on their Instagram pages.

A series of photos was shared to The Duke and Duchess of Cambridge's official Instagram account, including images of Prince William, Duchess Kate and more royal relatives.

"Wishing a very happy Birthday to The Prince of Wales!" the photos were captioned.

A photo of Prince Harry holding royal baby Archie at his christening while dad Charles looks on was shared to Harry and wife Meghan's account.

"Happy birthday to His Royal Highness The Prince of Wales - Sir, Pa, Grandpa!" the @SussexRoyal account captioned the photo with a cake emoji.

Charles is addressed as "Sir" by most people in the family, as "Pa" by his sons, and as "Grandpa" by his grandchildren.

The queen's Instagram account posted pictures of Charles as a baby, held by his father, Prince Philip, as the queen watches in the background, and a more recent picture of the Prince of Wales posing in a kilt at his Castle Mey in Scotland, the estate he inherited from his grandmother, the late Queen Mother.

Prince Andrew, the Duke of York, Charles' second brother, also posted birthday wishes with a picture of himself as a baby at his christening being held in the arms of his older brother.

"Happy Birthday to The Prince of Wales!⁣⁣ ⁣⁣To mark HRH’s 71st Birthday, here’s photo from 1960 of the then Prince Charles holding a baby Prince Andrew.," Andrew's post read.

As usual, Charles was working on his birthday: He is currently in India on a two-day trip, where he also received birthday well-wishes.

The royal was given a birthday card and cake from school children at a British Asian trust event in Mumbai on Thursday.

Earlier in the trip, Charles attended a round table conference with businessmen leaders in Mumbai. He also visited Gurudwara Bangla Sahib, the holy temple of Sikhs, in New Delhi on Wednesday. During his visit, he prepared Chapati bread with locals.

Posts about the the royal's experiences have been shared on the Clarence House Instagram account.

Britain's Prince Charles interacts with children from the Kaivalya Education Foundation supported by the British Asian trust, in Mumbai on Nov. 14, 2019.
Britain's Prince Charles interacts with children from the Kaivalya Education Foundation supported by the British Asian trust, in Mumbai on Nov. 14, 2019.

On Tuesday, before his departure, Charles took to the social media site to share a self-signed note.

According to Vanity Fair and People, of the account's more than 2,000 posts, this marks the first one written in the first person and signed by His Royal Highness.

In the post, which included a picture of the prince with his wife, Duchess Camilla, Charles praised the values of Sikhism ahead of his "tenth official visit" to India.

"I did just want to convey my warmest best wishes to all of you in the Sikh Community in the United Kingdom, and across the Commonwealth, on the 550th Birth Anniversary of Guru Nanak Dev Ji," he wrote. "The principles on which Guru Nanak founded the Sikh religion, and which guide your lives to this day, are ones which can inspire us all – hard work, fairness, respect, and selfless service to others."

Contributing: Charles Trepany

This article originally appeared on USA TODAY: Prince Charles birthday: Prince William, Prince Harry post photos