An Islamic State (IS) supporter who called for jihadis to attack Prince George at school was sending a clear message that the royal family should be targeted, a court has heard.
Husnain Rashid, of Nelson, Lancashire, also posted to potential lone wolves online suggestions of British football stadiums to strike following the deadly attack outside Besiktas's ground in Turkey, Woolwich Crown Court was told.
The 32-year-old, said to have taught at a mosque, allegedly called on supporters in a Telegram group on October 13 to target the four-year-old prince who started at Thomas's Battersea, in south-west London, a month earlier.
On Thursday, prosecutor Annabel Darlow told the court "the underlying message was clear" that "Prince George and other members of the royal family should be viewed as targets".
Rashid is charged with encouraging terrorism by posting a photograph of the prince at the school super-imposed with silhouettes of two masked jihad fighters.
"Even the royal family will not be left alone," a following message with the school's full address and postcode allegedly added. "School starts early."
The day after the December 2016 attack in Istanbul killing 38, Rashid posted a link to a Wikipedia list of UK football stadiums in order of capacity, the prosecution said.
"The underlying message clearly intended by the defendant was clear: encourage lone wolf jihadists, mujahideen operating on British soil, to launch an attack on those watching events in stadiums in this country and suggesting how to maximise the impact," Ms Darlow said.
A magazine he was producing also contained suggestions to strike the 2018 World Cup in Russia with vehicles, weapons or bombs, she said.
Rashid, said to have taught at the Muhammadi mosque, ran a "prolific" Telegram channel named the Lone Mujahid where he provided an "e-toolkit for terrorism", the prosecution claim.
This allegedly included a recipe for the poison ricin from the Islamist propaganda magazine Inspire, how to make Molotov cocktails and napalm, and a suggestion of poisoning supermarket ice creams.
He is accused of naming targets including British Army bases, shopping centres, Jewish communities and Government buildings, and planning to flee to Syria to fight for IS.
Rashid, of Leonard Street, has denied three counts of engaging in conduct in preparation of terrorist acts, one count of encouraging terrorism, two of dissemination of a terrorist publication and one of failing to comply with a notice under the Regulation of Investigatory Powers Act.
Rashid, charged with allegations spanning October 2016 to April this year, was arrested at his home in November.
The trial, expected to last six weeks, continues.