| February 2020 |
| 13/02/20 | The alliance FESO (today: OSEF) was founded. |
| Founding members::  Kalonek and  Glooba. |
|  The alliance reaches a population more than 100. |
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| 14/02/20 | Joining of:Pandragon, calimus, bro7, MAGICB, Thor77, archimedeciccio, Serval, Labriasoontir, Flèche, Deimos & Phobos, partti, Khroll, outlaw and on s'en fou. |
| The alliance reaches a population more than 1,000. |
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| 15/02/20 | Joining of:The Great King, alex 26, BaronCharles, Trag and Bouark. |
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| 16/02/20 | Joining of:nyaki, Wolf, patm37, Forcas and Jakja. |
| Leaving of:on s'en fou and The Great King. |
| The alliance reaches a population more than 5,000. |
|
| 17/02/20 | Joining of:Starscream, Mafox, froufrou, Anaj, Knight Solomon, Holda, Blackmamba, Joker and bob. |
| Leaving of:Serval alex 26 BaronCharles and Bouark. |
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| 18/02/20 | Joining of:Poutre, s.a.s.t., ☯Mi$tξRzξn☯ and Had. |
|  The alliance have their first conquest. |
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| 19/02/20 | Joining of:Midas and The Great King. |
| Leaving of:Trag and patm37. |
| Deletion of:partti and Wolf. |
| The alliance reaches a population more than 10,000. |
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| 20/02/20 | Joining of:Videodix and Paul. |
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| 21/02/20 | Joining of:Cali. |
| Leaving of:Jakja. |
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| 22/02/20 | Joining of:on s'en fou, Babouba, Bouark and duc de bronze. |
| Leaving of:Pandragon. |
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| 23/02/20 | Joining of:Winter and Lord Ahern. |
| Leaving of:s.a.s.t.. |
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| 24/02/20 | Joining of:Yiwit, Kano, Dawgsfan, Kepler and Ganesh. |
| Leaving of:Kano. |
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| 25/02/20 | Joining of:MCBINZ. |
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| 27/02/20 | Leaving of:Deimos & Phobos and Winter. |
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| 29/02/20 | Deletion of:Kepler. |
| March 2020 |
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| 02/03/20 | Joining of:Inutqen and Grochounix. |
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| 03/03/20 | Joining of:geant. |
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| 04/03/20 | Joining of:D-Rogue. |
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| 05/03/20 | Joining of:Panto. |
| Leaving of:Ganesh. |
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| 13/03/20 | Joining of:KUROKO33. |
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| 14/03/20 | Joining of:saiyuki, Clown, LeMarseillais, RIP-RAP, Hynga, Fuzz, Ancistrus, Eldhir, Horta, Zodan, Rilgar, CzłowiekPatryk, EnjoyThisOwn, shadday, Kraz, dunkjf, sasas, BreakPoint, Nhar Sheitan, Tymbark, Perceval, Dux Rupie, Queeℕ, leviking, Lemy, K⚔️K, Sinjin, Woodplayer and Bryfox. |
| The alliance reaches a population more than 50,000. |
| The alliance has done over 5 conquests. |
|
| 15/03/20 | The alliance is now known as OSEF. |
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| 16/03/20 | Joining of:Darckjador and Polo. |
| Leaving of:Polo. |
| The alliance reaches a population more than 100,000. |
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| 17/03/20 | Joining of:norbert and Stefan39. |
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| 18/03/20 | Joining of:ydalys, Sólyom, Nibbsch, Vietmin, KK HH and corrado_bp199. |
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| 19/03/20 | Joining of:Lord T and Matt. |
| Leaving of:Yiwit. |
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| 22/03/20 | Joining of:Drogel. |
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| 26/03/20 | Deletion of:Panto. |
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| 27/03/20 | Deletion of:archimedeciccio. |
| The alliance has done over 10 conquests. |
|
| 28/03/20 | Joining of:patm37, Serval, Trag and Deimos & Phobos. |
| Deletion of:KUROKO33. |
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| 29/03/20 | Joining of:alex 26. |
| Leaving of:Horta. |
| Deletion of:Mafox. |
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| 30/03/20 | Leaving of:Lord T. |
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| 31/03/20 | Joining of:Toro, Three Dragons, Devi, Red and noobie. |
| April 2020 |
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| 01/04/20 | Joining of:Ike, Aegon Targaryen and Hisoka. |
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| 03/04/20 | Leaving of:Dawgsfan D-Rogue and Eldhir. |
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| 04/04/20 | Joining of:LeWy. |
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| 05/04/20 | Joining of:Faust Paladin. |
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| 06/04/20 | Leaving of:sasas. |
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| 07/04/20 | Deletion of:LeWy. |
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| 10/04/20 | Joining of:Shankadra. |
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| 12/04/20 | Joining of:Jakja. |
| Leaving of:Lord Ahern. |
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| 13/04/20 | Joining of:Berserkir, Korona, NotSoPretty, Némesis, Kile and Crazy21. |
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| 14/04/20 | Joining of:okoska03, Astrylian, G & Z, Apa72, Paso, jonizuh, IsleOfWrath, Padawan and Pyromadness. |
| The alliance has done over 20 conquests. |
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| 15/04/20 | Joining of:Valarune. |
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| 16/04/20 | Joining of:Jain, Golyó and Jeanny. |
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| 17/04/20 | Joining of:POP and Ropiharczos. |
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| 18/04/20 | Deletion of:Sólyom. |
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| 19/04/20 | Joining of:kolii and Zuriel. |
| Leaving of:Forcas MCBINZ norbert corrado_bp199 Faust Paladin and Kile. |
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| 21/04/20 | Leaving of:Hynga and Trag. |
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| 22/04/20 | Joining of:Tompy and Ppetya. |
| Leaving of:Matt. |
| Deletion of:saiyuki and okoska03. |
| The alliance has done over 50 conquests. |
|
| 24/04/20 | Joining of:Cooper, Hjalte, Vector, FearLegion, Zion, Tana, BloodSeeker, Airs, Béka, ZombieUnicorn, octavia, Nonagenarian, Cailian, Fengel, Jarbear, latenkaveri, baltazar, Milton, Lunchbox, Madlano, urosuros, Foxfire, Ernie's, bigboss, Bomulos, Objak and hadiali405. |
| Leaving of:octavia baltazar and Lunchbox. |
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| 25/04/20 | Joining of:Mrtinc, rafiki, Shalltear, DMK, Sookie and RIP Master. |
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| 26/04/20 | Joining of:Xing and Aliz. |
| Leaving of:hadiali405. |
| Deletion of:bro7. |
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| 27/04/20 | Joining of:Pickeye and Shogun317. |
| The alliance reaches a population more than 500,000. |
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| 28/04/20 | Leaving of:nyaki and Crazy21. |
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| 30/04/20 | Joining of:TOMTOM and Tazam. |
| Deletion of:Sookie. |
| May 2020 |
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| 02/05/20 | Leaving of:Inutqen. |
| Deletion of:Toro. |
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| 06/05/20 | Leaving of:Stefan39. |
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| 08/05/20 | The alliance has done over 100 conquests. |
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| 15/05/20 | Deletion of:Cailian. |
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| 17/05/20 | Leaving of:Drogel. |
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| 18/05/20 | Leaving of:Videodix. |
| Deletion of:DMK. |
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| 22/05/20 | Deletion of:Grochounix. |
| June 2020 |
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| 02/06/20 | Leaving of:☯Mi$tξRzξn☯ Madlano and Aliz. |
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| 05/06/20 | Joining of:☯Mi$tξRzξn☯. |
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| 09/06/20 | Leaving of:latenkaveri. |
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| 11/06/20 | Joining of:latenkaveri. |
| Leaving of:Zodan TOMTOM and latenkaveri. |
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| 20/06/20 | The alliance has done over 200 conquests. |
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| 26/06/20 | Leaving of:Woodplayer. |