It is the first time in the illustrious history of Ajax the club have won their domestic title four years in a row.
As per Reuters:
Lasse Schone's early goal set up Ajax for an afternoon of celebration but Simon Cziommer's equaliser in the 22nd minute ensured a nervy finish as Ajax opened up an unassailable lead at the top of the table to seal the title.
To find Ajax's last Eredivisie defeat you have to go back to early November 2013, when they were beaten 1-0 at home by Vitesse.
Since then Frank de Boer's team have won 15 games and drawn six. With just one game of the season remaining, Ajax lead Feyenoord by four points after their draw on Sunday, ensuring the title will once again be theirs.
Former Ajax player de Boer was named the club's manager in 2010, having already spent time working their youth team.
His team won the title in his first season and have now done so in the three since. It's Little wonder de Boer's name is being linked with other big clubs—amongst them Tottenham, as per Luke Edwards of The Telegraph (via Tony Mogan of the International Business Times).
It seems doubtful, however, that Ajax would let him leave without a fight.