Final answer:
To match the year 1973 to an event in nursing history, research into documents like On All Frontiers: Four Centuries of Canadian Nursing is needed, though the question does not specify the event. A broad context, including the significant roles played by Canadian nursing in various wars and times, would be considered to find the corresponding historical development.
Step-by-step explanation:
The question requires matching the year 1973 to a significant historical development in nursing. To identify such a development, one can refer to the historical literature on Canadian nursing, such as On All Frontiers: Four Centuries of Canadian Nursing, and look for notable events or legislative decisions made during that year. The editorial from the Medical Journal of Australia mentioned with the date 1973 may discuss a relevant milestone in the nursing profession, possibly in connection with global nursing developments or specifically related to Canadian nurses, as evidenced by the historical documentation on Canadian nursing provided in the resources.
However, without a specific event listed for the year 1973, one would need to conduct more research into the history of nursing. This could involve examining the contributions of Canadian nurses during wartime, as depicted in the figure May 1917, or comparing the experiences of nurses during different times, for example, by reading letters from World War I and II.