Question: In what year did Henry I of Castile's grandather sign a peace treaty guaranteeing his successorship to the throne of England?

Context articles: U.S.–German Peace Treaty (1921)
Treaty of Tartu (Russian–Estonian)
Treaty of Niš (1739)
Russia–Chechen Peace Treaty
Treaty of Taipei
Treaty of San Francisco
Henry II of England
U.S.–Hungarian Peace Treaty (1921)
U.S.–Austrian Peace Treaty (1921)
Henry I of Castile

The U.S.—German Peace Treaty is a peace treaty between the U.S. and German governments, signed in Berlin on August 25, 1921, in the aftermath of World War I.
 The main reason for the conclusion of that treaty was the fact that the U.S. Senate did not consent to ratification of the multilateral peace treaty signed in Versailles, thus leading to a separate peace treaty.
 Ratifications were exchanged in Berlin on November 11, 1921, and the treaty became effective on the same day.
 The treaty was registered in "League of Nations Treaty Series" on August 12, 1922.
Tartu Peace Treaty (Estonian: "Tartu rahu" , literally "Tartu peace") or Treaty of Tartu was a peace treaty between Estonia and Soviet Russia signed on February 2, 1920 ending the Estonian War of Independence.
 The terms of the treaty stated that ""Russia unreservedly recognises"" the independence of Republic of Estonia "de jure" and renounced in perpetuity all rights to the territory of Estonia.
 Ratifications of the treaty were exchanged in Moscow on March 30, 1920.
 It was registered in "League of Nations Treaty Series" on July 12, 1922.
The Treaty of Niš was a peace treaty signed on 3 October 1739 in Niš (East Serbia), by the Ottoman Empire and Russian Empire, to end the Russo-Turkish War of 1735-1739.
 The Russians gave up their claim to Crimea and Moldavia but were allowed to build a port at Azov, though without fortifications and without the right to have a fleet in the Black Sea.
 The war was the result of a Russian effort to gain Azov and Crimea as a first step towards dominating the Black Sea.
 The Habsburg Monarchy entered the war in 1737 on the Russian side, but was forced to make peace with Ottomans at the separate Treaty of Belgrade, surrendering Northern Serbia, Northern Bosnia and Oltenia, and allowing the Ottomans to resist the Russian push toward Constantinople.
 In return, the Sultan acknowledged the Habsburg Emperor as the official protector of all Ottoman Christian subjects ("see Ottoman millet"), a position also claimed by Russia.
 The Austrian peace treaty compelled Russia to accept peace at Niš, ending the war with a partial Russian victory.
Russian-Chechen Peace Treaty, also known as the Moscow Peace Treaty, was a formal peace treaty "on peace and the principles of Russian-Chechen relations" following the First Chechen War of 1994-1996.
 It was signed by the president of Russia Boris Yeltsin and the newly elected president of Chechnya Aslan Maskhadov, on May 12, 1997, at the Moscow Kremlin.
The Sino-Japanese Peace Treaty (Chinese: 中日和平條約 ), commonly known as the Treaty of Taipei (), was a peace treaty between Japan and the Republic of China (ROC) signed in Taipei, Taiwan on April 28, 1952, and took effect on August 5 the same year, marking the formal end of the Second Sino-Japanese War (1937–45).
 This treaty was necessary, because neither the Republic of China nor the People's Republic of China was invited to sign the Treaty of San Francisco due to disagreements by other countries as to which government was the legitimate government of China during and after the Chinese Civil War.
 Under pressure from the United States, Japan signed a separate peace treaty with the Republic of China to bring the war between the two states to a formal end with a victory for the ROC.
 Although the ROC itself was not a participant in the San Francisco Peace Conference due to the resumption of the Chinese Civil War after 1945, this treaty largely corresponds to that of San Francisco.
 In particular, the ROC waived service compensation to Japan in this treaty with respect to Article 14(a).1 of the San Francisco Treaty.
Treaty of San Francisco (サンフランシスコ講和条約 , San-Furanshisuko kōwa-Jōyaku ) , or commonly known as the Treaty of Peace with Japan, Peace Treaty of San Francisco, or San Francisco Peace Treaty), mostly between Japan and the Allied Powers, was officially signed by 48 nations on September 8, 1951, in San Francisco.
 It came into force on April 28, 1952 and officially ended the American-led Allied Occupation of Japan.
 According to Article 11 of the Treaty, Japan accepts the judgments of the International Military Tribunal for the Far East and of other Allied War Crimes Courts imposed on Japan both within and outside Japan.
Henry II (5 March 1133 – 6 July 1189), also known as Henry Curtmantle (French: "Court-manteau" ), Henry FitzEmpress or Henry Plantagenet, ruled as Count of Anjou, Count of Maine, Duke of Normandy, Duke of Aquitaine, Count of Nantes, King of England and Lord of Ireland; at various times, he also controlled Wales, Scotland and Brittany.
 Henry was the son of Geoffrey of Anjou and Matilda, daughter of Henry I of England.
 He became actively involved by the age of 14 in his mother's efforts to claim the throne of England, then occupied by Stephen of Blois, and was made Duke of Normandy at 17.
 He inherited Anjou in 1151 and shortly afterwards married Eleanor of Aquitaine, whose marriage to Louis VII of France had recently been annulled.
 Stephen agreed to a peace treaty after Henry's military expedition to England in 1153, and Henry inherited the kingdom on Stephen's death a year later.
The U.S.–Hungarian Peace Treaty is a peace treaty between the United States and the Kingdom of Hungary, signed in Budapest on August 29, 1921, in the aftermath of the First World War.
 This separate peace treaty was required because the United States Senate refused to ratify the multilateral Treaty of Trianon.
The U.S.–Austrian Peace Treaty is a peace treaty between the United States and Austria, signed in Vienna on August 24, 1921, in the aftermath of the First World War.
 This separate peace treaty was required because the United States Senate refused to advise and consent to the ratification of the multilateral Treaty of Saint-Germain-en-Laye of 1919.
Henry I of Castile (14 April 1204 – 6 June 1217) was king of Castile.
 He was the son of Alfonso VIII of Castile and Eleanor of England, Queen of Castile (daughter of Henry II of England and Eleanor of Aquitaine).