Meanings of laboured of in English

Everyone puts in the effort but this feels laboured of late.

The picture, although a great work of art, and the most laboured of all his paintings, failed to satisfy the artist.

So men laboured of old time, whether with plough or sickle or pruning-hook, in the days when Augustan Virgil heard the garrulous swallow, still garrulous.

The "Knight's Tale," the longest and most laboured of Chaucer's stories, possesses a degree of regularity which might satisfy the most severe critic.