2 adjectives to describe laboriousness

Why," he added, "I was reading a book the other day, the life of Fitzherbert, you know, who was a man of prodigious laboriousness, who died early, worn out.

The greater complication thus introduced into business was overcome by the Roman merchant through his punctual laboriousness and his system of management by slaves and freedmen which, regarded from the point of view of the pure capitalist, was far preferable to our counting-house system.

2 adjectives to describe  laboriousness