When did Jesus institute the sacrament of Holy Orders?

"Jesus Christ instituted the Sacerdotal Order at the Last Supper when he conferred on the Apostles and their successors the power of consecrating the Blessed Eucharist. Then on the day of His resurrection He conferred on them the power of remitting and retaining sin, thus constituting them the first Priests of the New Law in all the fullness of their power."
(From the Catechism of St. Pius X)