Queen Elizabeth spent a night in hospital for “preliminary investigations” after cancelling a trip to Northern Ireland on the advice of her doctors.

A Buckingham Palace spokesperson said, “Following medical advice to rest for a few days, The Queen attended hospital on Wednesday afternoon for some preliminary investigations, returning to Windsor Castle at lunchtime today, and remains in good spirits.”

After announcing she had cancelled her trip, a spokesperson told the press, “The Queen has reluctantly accepted medical advice to rest for the next few days. Her Majesty is in good spirits and is disappointed that she will no longer be able to visit Northern Ireland, where she had been due to undertake a series of engagements today and tomorrow.

“The Queen sends her warmest good wishes to the people of Northern Ireland, and looks forward to visiting in the future.”

Prior to her hospitalisation, the Queen had been seen driving her Landrover and walking her dogs on her Windsor estate. The MIrror reported that she was “showing slight signs of a seasonal cold”, and that her illness was not believed to be COVID-19 related.

The newspaper reported that Her Majesty had been feeling “a little tired” after hosting a reception at Windsor Castle for the Global Investment Summit on Tuesday evening. Guests included billionaire business leaders like Bill Gates and politicians like Boris Johnson and John Kerry. The summit was held ahead of the COP26 climate summit taking place next month in Glasgow.

After returning to Windsor Castle on Thursday afternoon, the Queen was quickly back at her desk and undertaking some light duties.

Queen Elizabeth is known for her excellent health, and her visits to the hospital are few and far between. The last time the 95-year-old monarch is thought to have spent a night in hospital was in 2013, when she was suffering from symptoms of gastroenteritis.

Image: Ben Stansall – WPA Pool/Getty Images

This article first appeared on Over60.