King Charles III addressed Parliament for the first time as Britain’s monarch on Monday.

King Charles III was proclaimed as the new monarch of England on Saturday after his mother Queen Elizabeth II passed away last week. In his declaration at St James’s Palace, he paid tribute to his late mother Queen Elizabeth II and spoke of the “great inheritance and of the duties and heavy responsibilities of Sovereignty which have now passed to me.”

Addressing the assembled dignitaries, King Charles paid tribute to his mother, he said, “It is my most sorrowful duty to announce to you the death of my beloved Mother, The Queen.”

The Queen, the UK’s longest-reigning monarch, died peacefully at Balmoral Castle on Thursday afternoon at the age of 96.

“My Mother’s reign was unequalled in its duration, its dedication and its devotion. Even as we grieve, we give thanks for this most faithful life. I am deeply aware of this great inheritance and of the duties and heavy responsibilities of Sovereignty which have now passed to me. In taking up these responsibilities, I shall strive to follow the inspiring example I have been set in upholding constitutional government and to seek the peace, harmony and prosperity of the peoples of these Islands and the Commonwealth Realms and Territories throughout the world,” said the new King of UK.

King Charles Philip Arthur George paid tribute to his mother, Queen Elizabeth II, and spoke of the “great inheritance and of the duties and heavy responsibilities of Sovereignty.”

The death of the Queen was formally announced by the Accession Council before Charles III was named king. The 200 or so people gathered in the room all then said ‘God save the King’ before documents were signed.

He further reiterated his willingness and intention to continue the tradition of surrendering the hereditary revenues, including the Crown Estate.

“I take this opportunity to confirm my willingness and intention to continue the tradition of surrendering the hereditary revenues, including the Crown Estate, to My Government for the benefit of all, in return for the Sovereign Grant, which supports My official duties as Head of State and Head of Nation,” added King Charles.

The death of the 96-year-old Queen ended a generation-spanning, seven-decade reign that made her a beacon of stability in a tumultuous world. The UK has entered a period of official mourning, with tributes pouring in from around the world.