Sixth Master was impresioned by Jahangeer ,a moghul King.
He wanted to subdue the Faith or sikhism at that time and due to that only Father of Sixth Master,The Fifth Master was made to sit on red hot pan and that lead to his going away from earth and union with Akal.
after puting Sixthe Master in gwalior prison at later date there were a good lot of unhappy events in the family of Moghul king so his wife went to the cout of sufi of Chisti order Hazrat Nizamudddin of Delhi.
while she was stating the problem another sufi from Mian Meer side (of Punjab) interwened and told that there will be more problems as sin of imprisioning Great Worshipper of Allah is causing unrest and ailment.
And that was Sixth Master.It was decided to release Sixth Master who by that time had even Jailor becoming his desiple.
Guru Hargobind Sahib(Sixth master Said). There are 52 more of humans(Rajas or Kings mostly hindus perhpas) in jail and i want thier release or els I will stay here.
Ruler said as much of them who clould hold the corner of your cloath or your hands can leave the jail.
Guru got Made 50 corner cloath.50 people heald that cloath and 2 held his hand and all left the jail.
That made these Kings also Sikh of Guru.The day of release was same as Dewali so on Dewali we can call it bandi(prisioner's) Chor(Release) day. Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-youth/7776-hey-i-need-help.html
Das know one of the King called Baldev Singh or Ballu Raja ,a Tewatia Jaat,Who made Ballabhgarh Kingdom near Delhi south of Faridabad.
Last of then Nahar Singh Died figthing Britshers during 1857 war of independance.
Still we have one village of Tewatias near Ballabhgarrh called Dayalpur(towen of mercyfull(Dayal) Guru).
The people there still fallow many Sikh customs but are still Sahijdharis and no attempt was made to convert them.
(Das want to put that some part of story are taken from a book das bought from Gurudwara Sahihb in Delhi say there could be political unrest in Punjab(due to unjust deeds done to Gurus) instead of sickness in moghuls that might have caused the relaes of Guru)