Eugenio Lascorz y Labastida (26 March 1886 – 1 June 1962) was a Spanish lawyer who claimed to be a descendant of the medieval Laskaris family, which had ruled the Byzantine Empire in Nicaea from 1204 to 1261.

He combined that legal career with historical and literary studies focused on Ancient and Byzantine Greece, publishing works of both fiction and non-fiction that explored what he regarded as the history of his ancestors.

In 1923 he proclaimed himself to the Greek people as the legitimate heir to the throne of the historical Byzantine Empire and as claimant to the crown of the modern Kingdom of Greece.

After the outbreak of the Spanish Civil War in 1936, Lascorz served as a military judge in the Nationalist forces led by General Francisco Franco.

In 1943, Lascorz resigned his judgeship and moved to Madrid, where he dedicated himself full time to his dynastic claims and to the government of his orders of chivalry.

The exposure of his Byzantine genealogy as fraudulent caused a minor scandal within the high society of Madrid in 1953 and 1954, but Lascorz persisted in his claims until his death in 1962.

[6] The Lascorz family emigrated from the village of Plan to Zaragoza in the third quarter of nineteenth century, part of the large influx of immigrants from rural Aragon to its capital at around that time.

[11] Manuel's obituaries stated that he was a "descendant and heir of the ancient Greek imperial family of the same surname, fleeing from the ruins of his homeland".

[15] He embarked on a campaign attempting to secure recognition of his royal descent by changing his legal identity substituting "Lascorz" for "Láscaris" and seeking approval in Spanish courts.

Lascorz believed his descent from the Laskarids could give him a claim to the throne of the Kingdom of Greece, an idea which he dedicated the rest of his life to.

[16] At the time, Greece was embroiled in a succession crisis; social tension and the abdication of King Constantine I put the future of the ruling House of Glücksburg in doubt.

[14] In 1923, Lascorz issued a manifesto to the Greek people, proclaiming himself "Prince Eugene Lascaris Comnenus, heir to the Emperors of Byzantium and Pretender to the Throne of Greece".

The Láscaris family archives contain documents which they claim were sent in the early 1920s by Eleftherios Venizelos, the former prime minister of Greece, during his self-exile in Paris, supposedly seriously considering Lascorz as a candidate for the Greek throne.

[25] During the Spanish Civil War (1936 – 1939), Lascorz served as honorary captain of the Aragonese Requeté, an armed group that fought alongside General Francisco Franco's Nationalist faction and which was directly tied to the traditionalist and legitimist movement known as "Carlism".

[25] In 1956, Lascorz published "Caliniki: Evocación histórica", a short story centering on a fictional Lacedaemonian girl named Cali Cabasileas who falls in love with Andrónico, a courtier of Despot Manuel Kantakouzenos.

[39] Palacio alleged that Lascorz had used his knowledge of the Spanish legal system and the complicity or ignorance of certain officials in order to alter his name and present himself as a descendant of the Laskaris dynasty and, consequently, as a legitimate claimant to the Greek throne.

Its final report, issued on 18 June, vindicated Palacio and concluded that the Lascorz family's dynastic claims were deliberate fabrications.

[45] His son and heir Teodoro Láscaris, argued that the campaign against Eugenio carried out by Cadenas, Palacio, and others associated with Hidalguía had a political motivation.

According to Teodoro, leading figures behind Hidalguía were part of a rival current within the National Movement supporting General Franco, namely Falangists.

Teodoro also alleged that the campaign against his father was precipitated by the death of Carlist claimant Archduke Karl Pius (known to his supporters as "Carlos VIII") on 24 December 1953.

In his proclamation, Lascorz stressed his supposed descent from "Prince Andronikos Theodoros Laskaris", "hero of the Greek War of Independence", and he ended the text with "Long live Greece!

[53] His death garnered some media attention, for instance being reported in the 26 July issue of the Colombian newspaper Diario de Boyacá and in the 15 August issue of the French newspaper Lyon-Information (also known as Independance), there under the article title L'Hellénisme en deuil: Son Altesse Impériale et Régent le Prince Flavius Eugène II Láscaris Comnène ("Hellenism in mourning: His Imperial and Royal Highness Prince Flavius Eugene II Lascaris Comnenus").

[4] His heir as "titular emperor" was his oldest son, Teodoro Láscaris-Comneno ("Theodore IX", 27 October 1921 – 20 September 2006), who moved across the Atlantic together with Eugenio's other male children, Juan Arcadio and Constantino.

[56] Teodoro propagated the idea that the Americas represent "New Byzantium" and the "Fourth Rome";[f] where Christian faith, Western thought, and Greek civilization would continue to survive.

[56] Teodoro's son Eugenio (born on 10 October 1975), or Eugene III Theodore Emmanuel Lascaris Comnenus, maintains his family's claims.