Dates on the grid are guideposts. Ancient calendars, local seasons, and contemporary traditions differ; the linked sources explain what is attested and what is a modern choice.
Historical season · Opening of the old summer season · dates vary
Sigrblót / Summer Nights
A summer opening and offering for victory appears among the three seasonal offerings named in Ynglinga saga.
Present-day dates differ by calendar and community; this marker is a reading prompt, not a fixed historical date.