(I will sing the yondermost realms conterminous with the gliding world, which lie broadly open to spirits, which render to each the reward of his merits); […]

On the semantic level we understand as obligatory those modifications about which the speaker has an important information so that he must be able to answer a wh-question formed by the listener in the case that there is an ellipsis of the given member of the sentence on the syntactic level. The necessity to be able to answer a wh-question is thus a criterion distinguishing obligatory and optional modifications.

But when the earl held a Thing, then Thorkell spoke on behalf of the freemen, told the need of the men, and bade the earl spare his people.

In particular, the timings of Matlock trains will be tweaked with a view to achieving clockface timings a year later.