Jozo Simunovic and Mikael Lustig also achieved the feat
Celtic completed their Scottish Premiership season unbeaten on Sunday afternoon.
Brendan Rodgers' side defeated Hearts 2-0 to end the 2016-17 campaign with 34 wins and four draws. The team finished on a record-breaking 106 points, scoring 106 goals and only conceding 25.
Celtic's win is the first time a Scottish team has recorded the feat since the 1888-89 Rangers side that won all 18 of their matches.
While the achievement puts Celtic into Scottish history books, three of their player had already achieved the unusual feat and are now 'Double Incincibles'.
Kolo Toure, Mikael Lustig and Jozo Simunovic had all previously won a domestic title with an unbeaten team.
Toure's role in the team was not as evident as it was with the 2003-4 Arsenal team. The Ivorian defender played nine times this season in the league, compared to 37 out of a possible 38 thirteen years ago.
Lustig had a more active part to play in both of his teams, including the 2010 Rosenborg team. The Swede played 29 times out of 30 as the Norwegian side won their second title in a row. This year, he played in 29 games for Celtic to win his sixth Scottish title.
Croatian defender Jozo Simunovic played in his second unbeaten season in the space of three years. Two seasons ago, he played 20 times for Dinamo Zagreb as they won the Croatian title. In his first full season in Scotland, the 22-year-old, played 25 times.
To be part of a team that remains unbeaten in a league season is remarkable. To do it for two teams in different countries is outstanding.