Anatoly Ionov (Romanov claimant)
Anatoly Ionov( born 1936) is a Russian man who claims to be the son of Grand Duchess Anastasia Nikolaevna of Russia.
Grand Duchess Elizabeth Mikhailovna of Russia
Grand Duchess Elizabeth Mikhailovna of Russia( Moscow, 26 May
1826 – Wiesbaden, 28 January 1845) was the second child and daughter of Grand Duke Mikhail Pavlovich of Russia and Princess Charlotte of Württemberg who took the name" Elena Pavlovna" upon her conversion to the Orthodox faith.
Through her father, Elizabeth was a granddaughter of Tsar Paul I of Russia, and a niece of both Russian emperors Alexander I and Nicholas I.
Grand Duke Nicholas Konstantinovich of Russia
Grand Duke Nicholas Constantinovich of Russia( 14 February 1850 – 26 January 1918) was the first- born son of Grand Duke Konstantin Nikolayevich and Grand Duchess Alexandra Iosifovna of Russia and a grandson of Nicholas I of Russia.
Duchess Helene of Mecklenburg-Strelitz
Duchess Helene of Mecklenburg-Strelitz (16 January 1857 – 28 August 1936) was a daughter of Duke Georg August of Mecklenburg-Strelitz and his wife, Grand Duchess Catherine Mikhailovna of Russia.
She was the second wife of Prince Albert of Saxe-Altenburg.
Duke Georg Alexander of Mecklenburg-Strelitz
Duke Georg Alexander of Mecklenburg-Strelitz (6 June 1859 – 5 December 1909) was the eldest of the two surviving sons of Duke Georg August of Mecklenburg-Strelitz and of Grand Duchess Catherine Mikhailovna of Russia.
He was a great-grandson of Emperor Paul and a cousin of Emperor Alexander III of Russia.
Although he was a German prince of the House of Mecklenburg-Strelitz, he was raised in Imperial Russia, where he lived all his life.
He followed a career as an officer in the Russian army and was Major General, Commander of the Life Guard Dragoon Regiment.
Georg Alexander was a music lover, a skillful cellist and composer.
In 1896 he formed a private string quartet called the "Mecklenburg Quartet".
He contracted a morganatic marriage and his rights and inheritance passed to his younger brother Charles Michael, Duke of Mecklenburg.
His four children received the title of Counts of Carlow, but after Duke Georg Alexander's death, his unmarried brother adopted his son Georg, Count of Carlow, who became the heir to the House of Mecklenburg-Strelitz in 1934.
Grand Duchess Catherine Mikhailovna of Russia
Grand Duchess Catherine Mikhailovna of Russia  (28 August 1827 – 12 May 1894), was the third of five daughters of Grand Duke Michael Pavlovich of Russia (youngest son of Emperor
Paul I and Princess Sophie Dorothea of Württemberg) and Princess Charlotte of Württemberg (eldest child of Prince Paul of Württemberg and Princess Charlotte of Saxe-Hildburghausen).
Grand Duchess Olga Pavlovna of Russia
Grand Duchess Olga Pavlovna of Russia  was a "Grand Duchess of Russia" as the second youngest daughter and seventh child of Emperor Paul I of Russia and his empress consort, Sophie Dorothea of Württemberg.
Prince Dmitri Alexandrovich of Russia
Prince Dmitri Alexandrovich of Russia( 15 August 1901 – 7 July 1980) was the fourth son and fifth child of Grand Duke Alexander Mikhailovich of Russia and Grand Duchess Xenia Alexandrovna of Russia.
He was a nephew of Tsar Nicholas II of Russia.
Grand Duke Michael Pavlovich of Russia
Grand Duke Michael Pavlovich of Russia ("Mikhail Pavlovich")
(8 February 1798
[OS 28 January] – 9 September 1849 [OS 28 August]) was a Russian prince, the tenth child and fourth son of Paul I of Russia and Sophie Dorothea of Württemberg.
He was born in St. Petersburg.
Abdul-Vahed Niyazov
' of Russia.

Question: Who is Grand Duchess Catherine Mikhailovna Of Russia's paternal grandfather?
Answer: Paul I of Russia