Russian opposition leader Alexei Navalny marked his 45th birthday in prison on Friday.

In an Instagram post, Navalny thanked his family and supporters at the end of a year in which he described "strange things" happening to him. His wife, Yulia, shared a picture of the two of them in better times with "happy birthday" and a heart emoji in the caption.

Navalny's press secretary tweeted her congratulations to "the world's best boss and future president."

What 'strange things' happened to Navalny in the last year?

Navalny survived a poisoning by the chemical nerve agent Novichok on a flight from the eastern Russian city of Tomsk to Moscow in August.

He was then flown to Germany for treatment. On January 17 this year, he returned to Moscow and was taken into custody upon arrival at the airport.

A Moscow court then sentenced him to several years in a penal colony. He is currently serving time in Vladimir, 100 kilometers (62 miles) east of Moscow.

What lessons has Navalny taken from this last year of his life?

Navalny reassured his supporters about his mental health in a lengthy post on Instagram.

"I hope I can say today that the achievement of the year is that I'm kind of staying away from the 'beast in a cage' state for now," he wrote. "Thank you all, I hug everyone."

How is the Russian government marking the occasion?

Russian President Vladimir Putin signed into law a prohibition on leaders of so-called extremist organizations from running for office and participating in other ways, such as by donating or consulting, Russian outlet Mediazona reported.

The Russian state news agency Interfax reported that bailiffs searched Navalny's property for money and valuables, claimingthat  he owes 29 million rubles (€327,000/$397,000) in damages.

dpa contributed to this report