Histoires Tragiques, written by Francois de Belleforest as the end of the 16th century neared, has long been pinned as a source of inspiration for Shakespeare’s "Hamlet." Now, as reported by The Guardian on Monday the 5, Shakespearean scholar, John Casson, has discovered markings that he believes were made by the playwright himself.

The text, written in French in 1576, is a compilation of shorter pieces, one of which tells a story similar to that of Hamlet. Bellefort’s piece tells of a Danish prince named Amleth who experiences the same trials and tribulations that Hamlet did, the only difference being in the addition of an affair between Amleth’s mother and uncle during the former’s marriage to the king.

According to Casson, the majority of the annotations made in this copy of the Histoires were next to the section on "Amleth," and stopped abruptly after. To him, “It’s like he read the "Hamlet" section, moved into the next section and then stopped” (The Guardian).

Why does Casson believe Shakespeare himself made the markings? To him, it’s all in the timing. Historical context of an underlined passage, “the right of succession is a better way (to choose a monarch) than that of election,” helped point him to his conclusion. We know that "Hamlet" was written circa 1601; Casson believes that the underlining of the passage predates the seating of James I on the English throne in 1603. King James had two sons, making secession a non-issue in that time period.