Padmini, also known as Padmavati, was a legendary 13th-14th-century Indian queen. The earliest source to mention her is Padmavat, an epic poem written by Malik Muhammad Jayasi in 1540 CE.
"Padmavati was an exceptionally beautiful princess of the Singhal kingdom (Sri Lanka). Ratan Sen, the Rajput ruler of Chittor, heard about her beauty from a talking parrot named Hiraman. After an adventurous quest, he married her and brought her to Chittor. Alauddin Khilji, the Sultan of Delhi also heard about her beauty, and attacked Chittor to obtain her. Meanwhile, Ratan Sen was killed in a combat with Devpal, the king of Kumbhalner who was also enamoured with Padmavati's beauty. Before Alauddin Khilji could capture Chittor, Padmavati and her companions committed Jauhar (self-immolation) to protect their honour."
Padmavat:
Is an epic poem written in 1540 CE by Malik Muhammad Jayasi. Jayasi himself suggests that is meant to be an allegory, not a narration of a historical event.
It is a fictionalized version of the historic siege of Chittor by Alauddin Khilji in 1303 CE, who attacks Chittor after hearing of the beauty of Queen Rani Padmini, the wife of King Rawal Ratan Singh.
According to Jayasi, Chitor stood for body, Raja for mind, Ceylon for heart, Padmini for wisdom, Alauddin for lust, and Ashraf Jahangir Semnani as an ideal spiritual guide.
Other versions of the legend:
Persian and Urdu adaptations
Between 16th and 19th centuries, at least 12 Persian and Urdu translations or adaptations of Malik Muhammad Jayasi's Padmavat were produced. More Urdu versions appeared in the 20th century, all adhering to Jayasi's love poetry tradition.
Rajput ballads
In 1589 CE, Hemratan composed Gora Badal Padmini Chaupai, the first Rajput adaption of the legend, presenting it as a "true tale". Between 16th and 18th centuries, more Rajput versions of the Padmavati legend were compiled in present-day Rajasthan, under the patronage of the Rajput chiefs. Unlike Jayasi's theme of courting and marriage, the Rajput adaptions emphasized their honour in defending their kingdom against Alauddin Khilji.
James Tod's version
During 1829-32, James Tod included a colonial re-telling of the legend in his Annals and Antiquities of Rajas'han. His version was based on the information compiled from the oral and textual traditions of writers employed by the Rajput chiefs. Epigraphic evidence contradicts James Tod's claim that the contemporary ruler of Mewar was Lakshmanasimha (Lachhman Singh), not Ratnasimha (Ratan Singh or Ratan Sen).
Bengali adaptions
From late 19th century onward, several Bengali versions of legend were produced, when James Tod's work reached there. These Bengali narratives portrayed Padmavati as a Hindu queen who immolated herself to protect her honour against a lustful Muslim invader.
If she wasn't real then how did she become a historical figure and monuments were made in her name?
When the British writer James Tod, who is now considered to be unreliable, compiled the legends of Rajasthan in the 1820s, he presented Padmini as a historical figure, and Padmini came to be associated with the historical siege of Chittor. In the 19th century, during the Swadeshi movement, Padmini became a symbol of Indian patriotism. Indian nationalist writers portrayed her story as an example of a heroic sacrifice, and a number of plays featuring her were staged after 1905.
By the 20th century, some elite Rajput women of Rajasthan characterised Padmini as a historical figure who exemplifies Rajput womanhood. Although there is no historical evidence that Padmini existed, she has become a symbol of valour and sacrifice in Rajput history. Hindu activists have characterised her as a chaste Hindu woman, and her suicide as a heroic act of resistance against the invader Khilji.
Why does SLB's Padmavati's attire resembles Jodha's attire so much?
Because they're both from Rajasthan.
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